Date post: | 07-Aug-2015 |
Category: |
Health & Medicine |
Upload: | faisol-kabir |
View: | 183 times |
Download: | 28 times |
A 43 year old man is stabbed outside a nightclub. He suffers a transection of his median nerve just as it leaves the brachial plexus.
Which of the following features is least likely to ensue?
A. Ulnar deviation of the wrist
B. Complete loss of wrist flexion
C. Loss of pronation
D. Loss of flexion at the thumb joint
E. Inability to oppose the thumb
Next question
Loss of the median nerve will result in loss of function of the flexor muscles. However, flexor carpi ulnaris will still function and produce
ulnar deviation and some residual wrist flexion. High median nerve lesions result in complete loss of flexion at the thumb joint.
Median nerve
The median nerve is formed by the union of a lateral and medial root respectively from the lateral (C5,6,7) and medial (C8 and T1)
cords of the brachial plexus; the medial root passes anterior to the third part of the axillary artery. The nerve descends lateral to the
brachial artery, crosses to its medial side (usually passing anterior to the artery). It passes deep to the bicipital aponeurosis and the
median cubital vein at the elbow.
It passes between the two heads of the pronator teres muscle, and runs on the deep surface of flexor digitorum superficialis (within its
fascial sheath).
Near the wrist it becomes superficial between the tendons of flexor digitorum superficialis and flexor carpi radialis, deep to palmaris
longus tendon. It passes deep to the flexor retinaculum to enter the palm, but lies anterior to the long flexor tendons within the carpal
tunnel.
Branches
Region Branch
Upper arm No branches, although the nerve commonly communicates with the musculocutaneous nerve
Forearm Pronator teres
Flexor carpi radialis
Palmaris longus
Flexor digitorum superficialis
Flexor pollicis longus
Flexor digitorum profundus (only the radial half)
Distal
forearm
Palmar cutaneous branch
Hand (Motor) Motor supply (LOAF)
Lateral 2 lumbricals
Opponens pollicis
Abductor pollicis brevis
Flexor pollicis brevis
Hand
(Sensory) Over thumb and lateral 2 ½ fingers
On the palmar aspect this projects proximally, on the dorsal aspect only the distal regions are innervated with the radial nerve
providing the more proximal cutaneous innervation.
Patterns of damage
Damage at wrist
e.g. carpal tunnel syndrome
paralysis and wasting of thenar eminence muscles and opponens pollicis (ape hand deformity)
sensory loss to palmar aspect of lateral (radial) 2 ½ fingers
Damage at elbow, as above plus:
unable to pronate forearm
weak wrist flexion
ulnar deviation of wrist
Anterior interosseous nerve (branch of median nerve)
leaves just below the elbow
results in loss of pronation of forearm and weakness of long flexors of thumb and index finger
Topography of the median nerve
A 24 year old man falls and sustains a fracture through his scaphoid bone. From which of the following areas does the scaphoid
derive the majority of its blood supply?
A. From its proximal medial border
B. From its proximal lateral border
C. From its proximal posterior surface
D. From the proximal end
E. From the distal end
Next question
Theme from April 2012 Exam
The blood supply to the scaphoid enters from a small non articular surface near its distal end. Transverse fractures through the
scaphoid therefore carry a risk of non union.
Scaphoid bone
The scaphoid has a concave articular surface for the head of the capitate and at the edge of this is a crescentic surface for the
corresponding area on the lunate.
Proximally, it has a wide convex articular surface with the radius. It has a distally sited tubercle that can be palpated. The remaining
articular surface is to the lateral side of the tubercle. It faces laterally and is associated with the trapezium and trapezoid bones.
The narrow strip between the radial and trapezial surfaces and the tubercle gives rise to the radial collateral carpal ligament. The
tubercle receives part of the flexor retinaculum. This area is the only part of the scaphoid that is available for the entry of blood
vessels. It is commonly fractured and avascular necrosis may result.
A 56 year old man requires long term parenteral nutrition
and the decision is made to insert a PICC line for long
term venous access. This is inserted into the basilic vein
at the region of the elbow. As the catheter is advanced,
into which venous structure is the tip of the catheter most
likely to pass from the basilic vein?
A. Subclavian vein
B. Axillary vein
C. Posterior circumflex humeral vein
D. Cephalic vein
E. Superior vena cava
Next question
The basilic vein drains into the axillary vein and although
PICC lines may end up in a variety of fascinating locations
the axillary vein is usually the commonest site following
from the basilic. The posterior circumflex humeral vein is
encountered prior to the axillary vein. However, a PICC
line is unlikely to enter this structure because of its angle
of entry into the basilic vein.
Basilic vein
The basilic and cephalic veins both provide the main
pathways of venous drainage for the arm and hand. It is
continuous with the palmar venous arch distally and the
axillary vein proximally.
Path
Originates on the medial side of the dorsal venous
network of the hand, and passes up the forearm and
arm.
Most of its course is superficial.
Near the region anterior to the cubital fossa the vein
joins the cephalic vein.
Midway up the humerus the basilic vein passes deep
under the muscles.
At the lower border of the teres major muscle, the
anterior and posterior circumflex humeral veins feed
into it.
Joins the brachial veins to form the axillary vein.
Theme: Nerve injury
A. Ulnar nerve
B. Musculocutaneous nerve
C. Radial nerve
D. Median nerve
E. Axillary nerve
F. Intercostobrachial nerve
What is the most likely nerve injury for the scenario given?
Each option may be used once, more than once or not at
all.
16. A 23 year old man is involved in a fight outside a
nightclub and sustains a laceration to his right arm. On
examination he has lost extension of the fingers in his
right hand.
Radial nerve
The radial nerve supplies the extensor muscle group.
17. A 40 year old lady trips and falls through a glass door
and sustains a severe laceration to her left arm. Amongst
her injuries it is noticed that she has lost the ability to
adduct the fingers of her left hand.
Ulnar nerve
The interossei are supplied by the ulnar nerve.
18. A 28 year old rugby player injures his right humerus and
on examination is noted to have a minor sensory deficit
overlying the point of deltoid insertion into the humerus.
Axillary nerve
This patch of skin is supplied by the axillary nerve
Next question
Brachial plexus
Origin Anterior rami of C5 to T1
Sections of the
plexus
Roots, trunks, divisions, cords, branches
Mnemonic:Real Teenagers Drink Cold Beer
Roots Located in the posterior triangle
Pass between scalenus anterior and medius
Trunks Located posterior to middle third of clavicle
Upper and middle trunks related superiorly to the
subclavian artery
Lower trunk passes over 1st rib posterior to the
subclavian artery
Divisions Apex of axilla
Cords Related to axillary artery
Diagram illustrating the branches of the brachial plexus
Image sourced from Wikipedia
Cutaneous sensation of the upper limb
Image sourced from Wikipedia
A 21 year old man is stabbed in the antecubital fossa. A
decision is made to surgically explore the wound. At
operation the surgeon dissects down onto the brachial
artery. A nerve is identified medially, which nerve is it likely
to be?
A. Radial
B. Recurrent branch of median
C. Anterior interosseous
D. Ulnar
E. Median
Next question
Theme from September 2012 Exam
Median nerve
The median nerve is formed by the union of a lateral and
medial root respectively from the lateral (C5,6,7) and
medial (C8 and T1) cords of the brachial plexus; the
medial root passes anterior to the third part of the axillary
artery. The nerve descends lateral to the brachial artery,
crosses to its medial side (usually passing anterior to the
artery). It passes deep to the bicipital aponeurosis and the
median cubital vein at the elbow.
It passes between the two heads of the pronator teres
muscle, and runs on the deep surface of flexor digitorum
superficialis (within its fascial sheath).
Near the wrist it becomes superficial between the tendons
of flexor digitorum superficialis and flexor carpi radialis,
deep to palmaris longus tendon. It passes deep to the
flexor retinaculum to enter the palm, but lies anterior to the
long flexor tendons within the carpal tunnel.
Branches
Region Branch
Upper arm No branches, although the nerve commonly communicates
with the musculocutaneous nerve
Forearm Pronator teres
Flexor carpi radialis
Palmaris longus
Flexor digitorum superficialis
Flexor pollicis longus
Flexor digitorum profundus (only the radial half)
Distal
forearm
Palmar cutaneous branch
Hand
(Motor)
Motor supply (LOAF)
Lateral 2 lumbricals
Opponens pollicis
Abductor pollicis brevis
Flexor pollicis brevis
Hand
(Sensory)
Over thumb and lateral 2 ½ fingers
On the palmar aspect this projects proximally, on the
dorsal aspect only the distal regions are innervated with
the radial nerve providing the more proximal cutaneous
innervation.
Patterns of damage
Damage at wrist
e.g. carpal tunnel syndrome
paralysis and wasting of thenar eminence muscles
and opponens pollicis (ape hand deformity)
sensory loss to palmar aspect of lateral (radial) 2 ½
fingers
Damage at elbow, as above plus:
unable to pronate forearm
weak wrist flexion
ulnar deviation of wrist
Anterior interosseous nerve (branch of median nerve)
leaves just below the elbow
results in loss of pronation of forearm and weakness
of long flexors of thumb and index finger
Topography of the median nerve
Image sourced fro
A man sustains a laceration between the base of the little
finger and wrist. Several weeks after the injury there is
loss of thumb adduction power. Which nerve is most likely
to have been injured?
A. Superficial ulnar nerve
B. Deep ulnar nerve
C. Median nerve
D. Radial nerve
E. Recurrent branch of median nerve
Next question
Theme from 2009 Exam
Ulnar nerve injury at wrist
Branches of the ulnar nerve in the wrist and hand
At the wrist the ulnar nerve divides into superficial and
deep branches. The superficial branch lies deep to the
palmaris brevis. It divides into two; to produce digital
nerves, which innervate the skin of the medial third of the
palm and the palmar surface of one and a half fingers.
The deep branch arises from the nerve on the flexor
retinaculum lateral to the pisiform bone. It passes
posteriorly between the abductor and short flexor of the
little finger supplying them, and supplying and piercing the
opponens digiti minimi near its origin from the flexor
retinaculum, turns laterally over the distal surface of the
Hook of the Hamate bone. It eventually passes between
the two heads of adductor pollicis with the deep palmar
arch and ends in the first dorsal interosseous muscle. In
the palm the deep branch also innervates the lumbricals
and interosseous muscles.
A 25 year old man is stabbed in the upper arm. The
brachial artery is lacerated at the level of the proximal
humerus, and is being repaired. A nerve lying immediately
lateral to the brachial artery is also lacerated. Which of the
following is the nerve most likely to be?
A. Ulnar nerve
B. Median nerve
C. Radial nerve
D. Intercostobrachial nerve
E. Axillary nerve
Next question
The brachial artery begins at the lower border of teres
major and terminates in the cubital fossa by branching into
the radial and ulnar arteries. In the upper arm the median
nerve lies closest to it in the lateral position. In the cubital
fossa it lies medial to it.
Image sourced from Wikipedia
Brachial artery
The brachial artery begins at the lower border of teres
major as a continuation of the axillary artery. It terminates
in the cubital fossa at the level of the neck of the radius by
dividing into the radial and ulnar arteries.
Relations
Posterior relations include the long head of triceps with the
radial nerve and profunda vessels intervening. Anteriorly it
is overlapped by the medial border of biceps.
It is crossed by the median nerve in the middle of the arm.
In the cubital fossa it is separated from the median cubital
vein by the bicipital aponeurosis.
The basilic vein is in contact at the most proximal aspect
of the cubital fossa and lies medially.
What is the course of the median nerve relative to the
brachial artery in the upper arm?
A. Medial to anterior to lateral
B. Lateral to posterior to medial
C. Medial to posterior to lateral
D. Medial to anterior to medial
E. Lateral to anterior to medial
Next question
Relations of median nerve to the brachial artery:
Lateral -> Anterior -> Medial
Theme from 2009 and 2012 Exams
The median nerve descends lateral to the brachial artery,
it usually passes anterior to the artery to lie on its medial
side. It passes deep to the bicipital aponeurosis and the
median cubital vein at the elbow. It enters the forearm
between the two heads of the pronator teres muscle.
Image sourced from Wikipedia
Brachial artery
The brachial artery begins at the lower border of teres
major as a continuation of the axillary artery. It terminates
in the cubital fossa at the level of the neck of the radius by
dividing into the radial and ulnar arteries.
Relations
Posterior relations include the long head of triceps with the
radial nerve and profunda vessels intervening. Anteriorly it
is overlapped by the medial border of biceps.
It is crossed by the median nerve in the middle of the arm.
In the cubital fossa it is separated from the median cubital
vein by the bicipital aponeurosis.
The basilic vein is in contact at the most proximal aspect
of the cubital fossa and lies medially.
A 22 year old falls over and lands on a shard of glass. It
penetrates the palmar aspect of his hand, immediately
lateral to the pisiform bone. Which of the following
structures is most likely to be injured?
A. Palmar cutaneous branch of the median nerve
B. Lateral tendons of flexor digitorum superficialis
C. Ulnar artery
D. Flexor carpi radialis tendons
E. Lateral tendons of flexor digitorum profundus
Next question
The ulnar nerve and artery are at most immediate risk in
this injury. This is illustrated in the image below:
Image sourced from Wikipedia
Hand
Anatomy of the hand
Bones 8 Carpal bones
5 Metacarpals
14 phalanges
Intrinsic
Muscles
7 Interossei - Supplied by ulnar nerve
3 palmar-adduct fingers
4 dorsal- abduct fingers
Intrinsic
muscles
Lumbricals
Flex MCPJ and extend the IPJ.
Origin deep flexor tendon and insertion dorsal
extensor hood mechanism.
Innervation: 1st and 2nd- median nerve, 3rd and
4th- deep branch of the ulnar nerve.
Thenar
eminence
Abductor pollicis brevis
Opponens pollicis
Flexor pollicis brevis
Hypothenar
eminence
Opponens digiti minimi
Flexor digiti minimi brevis
Abductor digiti minimi
A motorcyclist is involved in a road traffic accident. He
suffers a complex humeral shaft fracture which is plated.
Post operatively he complains of an inability to extend his
fingers. Which of the following structures is most likely to
have been injured?
A. Ulnar nerve
B. Radial nerve
C. Median nerve
D. Axillary nerve
E. None of the above
Next question
Mnemonic for radial nerve muscles: BEST
B rachioradialis
E xtensors
S upinator
T riceps
The radial nerve is responsible for innervation of the
extensor compartment of the forearm.
Radial nerve
Continuation of posterior cord of the brachial plexus (root
values C5 to T1)
Path
In the axilla: lies posterior to the axillary artery on
subscapularis, latissimus dorsi and teres major.
Enters the arm between the brachial artery and the
long head of triceps (medial to humerus).
Spirals around the posterior surface of the humerus
in the groove for the radial nerve.
At the distal third of the lateral border of the humerus
it then pierces the intermuscular septum and
descends in front of the lateral epicondyle.
At the lateral epicondyle it lies deeply between
brachialis and brachioradialis where it then divides
into a superficial and deep terminal branch.
Deep branch crosses the supinator to become the
posterior interosseous nerve.
In the image below the relationships of the radial nerve
can be appreciated
Image sourced from Wikipedia
Regions innervated
Motor (main
nerve)
Triceps
Anconeus
Brachioradialis
Extensor carpi radialis
Motor
(posterior
Extensor carpi ulnaris
Extensor digitorum
interosseous
branch
Extensor indicis
Extensor digiti minimi
Extensor pollicis longus and brevis
Abductor pollicis longus
Sensory The area of skin supplying the proximal
phalanges on the dorsal aspect of the hand
is supplied by the radial nerve (this does
not apply to the little finger and part of the
ring finger)
Muscular innervation and effect of denervation
Anatomical
location
Muscle affected Effect of paralysis
Shoulder Long head of
triceps
Minor effects on
shoulder stability in
abduction
Arm Triceps Loss of elbow extension
Forearm Supinator
Brachioradialis
Extensor carpi
radialis longus and
brevis
Weakening of
supination of prone
hand and elbow flexion
in mid prone position
The cutaneous sensation of the upper limb- illustrating the
contribution of the radial nerve
A 48 year old lady is undergoing an axillary node
clearance for breast cancer. Which of the structures listed
below are most likely to be encountered during the axillary
dissection?
A. Cords of the brachial plexus
B. Thoracodorsal trunk
C. Internal mammary artery
D. Thoracoacromial artery
E. None of the above
Next question
Beware of damaging the thoracodorsal trunk if a latissimus dorsi
flap reconstruction is planned.
Theme from 2009 Exam
The thoracodorsal trunk runs through the nodes in the
axilla. If injured it may compromise the function and blood
supply to latissimus dorsi, which is significant if it is to be
used as a flap for a reconstructive procedure.
Axilla
Boundaries of the axilla
Medially Chest wall and Serratus anterior
Laterally Humeral head
Floor Subscapularis
Anterior aspect Lateral border of Pectoralis major
Fascia Clavipectoral fascia
Content:
Long thoracic nerve
(of Bell)
Derived from C5-C7 and passes behind the
brachial plexus to enter the axilla. It lies on the
medial chest wall and supplies serratus anterior.
Its location puts it at risk during axillary surgery
and damage will lead to winging of the scapula.
Thoracodorsal nerve
and thoracodorsal
Innervate and vascularise latissimus dorsi.
trunk
Axillary vein Lies at the apex of the axilla, it is the continuation
of the basilic vein. Becomes the subclavian vein
at the outer border of the first rib.
Intercostobrachial
nerves
Traverse the axillary lymph nodes and are often
divided during axillary surgery. They provide
cutaneous sensation to the axillary skin.
Lymph nodes The axilla is the main site of lymphatic drainage
for the breast.
53 year old lady is recovering following a difficult
mastectomy and axillary nodal clearance for carcinoma of
the breast. She complains of shoulder pain and on
examination has obvious winging of the scapula. Loss of
innervation to which of the following is the most likely
underlying cause?
A. Latissimus dorsi
B. Serratus anterior
C. Pectoralis minor
D. Pectoralis major
E. Rhomboids
Next question
Theme from April 2012 Exam
Winging of the scapula is most commonly the result of
long thoracic nerve injury or dysfunction. Iatrogenic
damage during the course of the difficult axillary dissection
is the most likely cause in this scenario. Damage to the
rhomboids may produce winging of the scapula but would
be rare in the scenario given.
Long thoracic nerve
Derived from ventral rami of C5, C6, and C7 (close to
their emergence from intervertebral foramina)
It runs downward and passes either anterior or
posterior to the middle scalene muscle
It reaches upper tip of serratus anterior muscle and
descends on outer surface of this muscle, giving
branches into it
Winging of Scapula occurs in long thoracic nerve
injury (most common) or from spinal accessory nerve
injury (which denervates the trapezius) or a dorsal
scapular nerve injury
A 23 year old man falls and slips at a nightclub. A shard of
glass penetrates the skin at the level of the medial
epicondyle, which of the following sequelae is least likely
to occur?
A. Atrophy of the first dorsal interosseous muscle
B. Difficulty in abduction of the the 2nd, 3rd, 4th and
5th fingers
C. Claw like appearance of the hand
D. Loss of sensation on the anterior aspect of the 5th
finger
E. Partial denervation of flexor digitorum profundus
Next question
Injury to the ulnar nerve in the mid to distal forearm will
typically produce a claw hand. This consists of flexion of the 4th
and 5th interphalangeal joints and extension of the
metacarpophalangeal joints. The effects are potentiated when
flexor digitorum profundus is not affected, and the clawing is
more pronounced.More proximally sited ulnar nerve lesions
produce a milder clinical picture owing to the simultaneous
paralysis of flexor digitorum profundus (ulnar half).
This is the 'ulnar paradox', due to the more proximal level
of transection the hand will typically not have a claw like
appearance that may be seen following a more distal
injury. The first dorsal interosseous muscle will be affected
as it is supplied by the ulnar nerve.
Ulnar nerve
Origin
C8, T1
Supplies (no muscles in the upper arm)
Flexor carpi ulnaris
Flexor digitorum profundus
Flexor digiti minimi
Abductor digiti minimi
Opponens digiti minimi
Adductor pollicis
Interossei muscle
Third and fourth lumbricals
Palmaris brevis
Path
Posteromedial aspect of ulna to flexor compartment
of forearm, then along the ulnar. Passes beneath the
flexor carpi ulnaris muscle, then superficially through
the flexor retinaculum into the palm of the hand.
Image sourced from Wikipedia
Branches
Branch Supplies
Articular branch Flexor carpi ulnaris
Medial half of the flexor digitorum
profundus
Palmar cutaneous branch (Arises
near the middle of the forearm)
Skin on the medial part of the palm
Dorsal cutaneous branch Dorsal surface of the medial part of the
hand
Superficial branch Cutaneous fibres to the anterior surfaces
of the medial one and one-half digits
Deep branch Hypothenar muscles
All the interosseous muscles
Third and fourth lumbricals
Adductor pollicis
Medial head of the flexor pollicis brevis
Effects of injury
Damage at the
wrist
Wasting and paralysis of intrinsic hand muscles
(claw hand)
Wasting and paralysis of hypothenar muscles
Loss of sensation medial 1 and half fingers
Damage at the
elbow
Radial deviation of the wrist
Clawing less in 3rd and 4th digits
A 43 year old lady is due to undergo an axillary node
clearance as part of treatment for carcinoma of the breast.
Which of the following fascial layers will be divided during
the surgical approach to the axilla?
A. Sibsons fascia
B. Pre tracheal fascia
C. Waldayers fascia
D. Clavipectoral fascia
E. None of the above
Next question
The clavipectoral fascia is situated under the clavicular
portion of pectoralis major. It protects both the axillary
vessels and nodes. During an axillary node clearance for
breast cancer the clavipectoral fascia is incised and this
allows access to the nodal stations. The nodal stations
are; level 1 nodes inferior to pectoralis minor, level 2 lie
behind it and level 3 above it. During a Patey Mastectomy
surgeons divide pectoralis minor to gain access to level 3
nodes. The use of sentinel node biopsy (and stronger
assistants!) have made this procedure far less common.
A 23 year old climber falls and fractures his humerus. The
surgeons decide upon a posterior approach to the middle
third of the bone. Which of the following nerves is at
greatest risk in this approach?
A. Ulnar
B. Antebrachial
C. Musculocutaneous
D. Radial
E. Intercostobrachial
Next question
Theme from April 2012 Exam
The radial nerve wraps around the humerus and may be
injured during a posterior approach. An IM nail may be
preferred as it avoids the complex dissection needed for
direct bone exposure.
Radial nerve
Continuation of posterior cord of the brachial plexus (root
values C5 to T1)
Path
In the axilla: lies posterior to the axillary artery on
subscapularis, latissimus dorsi and teres major.
Enters the arm between the brachial artery and the
long head of triceps (medial to humerus).
Spirals around the posterior surface of the humerus
in the groove for the radial nerve.
At the distal third of the lateral border of the humerus
it then pierces the intermuscular septum and
descends in front of the lateral epicondyle.
At the lateral epicondyle it lies deeply between
brachialis and brachioradialis where it then divides
into a superficial and deep terminal branch.
Deep branch crosses the supinator to become the
posterior interosseous nerve.
In the image below the relationships of the radial nerve
can be appreciated
Image sourced from Wikipedia
Regions innervated
Motor (main
nerve)
Triceps
Anconeus
Brachioradialis
Extensor carpi radialis
Motor
(posterior
interosseous
branch
Extensor carpi ulnaris
Extensor digitorum
Extensor indicis
Extensor digiti minimi
Extensor pollicis longus and brevis
Abductor pollicis longus
Sensory The area of skin supplying the proximal
phalanges on the dorsal aspect of the hand
is supplied by the radial nerve (this does
not apply to the little finger and part of the
ring finger)
Muscular innervation and effect of denervation
Anatomical
location
Muscle affected Effect of paralysis
Shoulder Long head of
triceps
Minor effects on
shoulder stability in
abduction
Arm Triceps Loss of elbow extension
Forearm Supinator
Brachioradialis
Extensor carpi
radialis longus and
brevis
Weakening of
supination of prone
hand and elbow flexion
in mid prone position
The cutaneous sensation of the upper limb- illustrating the
contribution of the radial nerve
Image sourced from Wikipedia
heme: Nerve injury
A. Median nerve
B. Ulnar nerve
C. Radial nerve
D. Posterior interosseous nerve
E. Anterior interosseous nerve
F. Musculocutaneous nerve
G. Axillary nerve
H. Brachial Trunks C5-6
I. Brachial trunks C6-7
J. Brachial Trunks C8-T1
Please select the most likely lesion site for each scenario.
Each option may be used once, more than once or not at
all.
83. A 42 year old teacher is admitted with a fall. An x-ray
confirms a fracture of the surgical neck of the humerus.
Which nerve is at risk?
Axillary nerve
The Axillary nerve winds around the bone at the neck of
the humerus. The axillary nerve is also at risk during
shoulder dislocation.
84. A 32 year old window cleaner is admitted after falling off
the roof. He reports that he had slipped off the top of the
roof and was able to cling onto the gutter for a few
seconds. The patient has Horner's syndrome.
Brachial Trunks C8-T1
The patient has a Klumpke's paralysis involving brachial
trunks C8-T1. Classically there is weakness of the hand
intrinsic muscles. Involvement of T1 may cause a
Horner's syndrome. It occurs as a result of traction
injuries or during delivery.
85. A 32 year old rugby player is hit hard on the shoulder
during a rough tackle. Clinically his arm is hanging loose
on the side. It is pronated and medially rotated.
Brachial Trunks C5-6
The patient has an Erb's palsy involving brachial trunks
C5-6.
Next question
Brachial plexus
Origin Anterior rami of C5 to T1
Sections of the Roots, trunks, divisions, cords, branches
plexus Mnemonic:Real Teenagers Drink Cold Beer
Roots Located in the posterior triangle
Pass between scalenus anterior and medius
Trunks Located posterior to middle third of clavicle
Upper and middle trunks related superiorly to the
subclavian artery
Lower trunk passes over 1st rib posterior to the
subclavian artery
Divisions Apex of axilla
Cords Related to axillary artery
Diagram illustrating the branches of the brachial plexus
Image sourced from Wikipedia
Cutaneous sensation of the upper limb
Image sourced
hich of the following nerves is responsible for innervation
of the triceps muscle?
A. Radial
B. Ulnar
C. Axillary
D. Median
E. None of the above
Next question
To remember nerve roots and their relexes:
1-2 Ankle (S1-S2)
3-4 Knee (L3-L4)
5-6 Biceps (C5-C6)
7-8 Triceps (C7-C8)
The radial nerve innervates all three heads of triceps, with
a separate branch to each head.
Triceps
Origin Long head- infraglenoid tubercle of the scapula.
Lateral head- dorsal surface of the humerus, lateral
and proximal to the groove of the radial nerve
Medial head- posterior surface of the humerus on the
inferomedial side of the radial groove and both of the
intermuscular septae
Insertion Olecranon process of the ulna. Here the olecranon
bursa is between the triceps tendon and olecranon.
Some fibres insert to the deep fascia of the forearm,
posterior capsule of the elbow (preventing the capsule
from being trapped between olecranon and olecranon
fossa during extension)
Innervation Radial nerve
Blood
supply
Profunda brachii artery
Action Elbow extension. The long head can adduct the humerus and
and extend it from a flexed position
Relations The radial nerve and profunda brachii vessels lie between the
lateral and medial heads
Which of the following muscles inserts onto the lesser
tuberostiy of the the humerus?
A. Subscapularis
B. Deltoid
C. Supraspinatus
D. Teres minor
E. Infraspinatus
Next question
With the exception of subscapularis which inserts into the
lesser tuberosity, the muscles of the rotator cuff insert into
the greater tuberosity.
Shoulder joint
Shallow synovial ball and socket type of joint.
It is an inherently unstable joint, but is capable to a
wide range of movement.
Stability is provided by muscles of the rotator cuff that
pass from the scapula to insert in the greater
tuberosity (all except sub scapularis-lesser
tuberosity).
Glenoid labrum
Fibrocartilaginous rim attached to the free edge of
the glenoid cavity
Tendon of the long head of biceps arises from within
the joint from the supraglenoid tubercle, and is fused
at this point to the labrum.
The long head of triceps attaches to the infraglenoid
tubercle
Fibrous capsule
Attaches to the scapula external to the glenoid
labrum and to the labrum itself (postero-superiorly)
Attaches to the humerus at the level of the
anatomical neck superiorly and the surgical neck
inferiorly
Anteriorly the capsule is in contact with the tendon of
subscapularis, superiorly with the supraspinatus
tendon, and posteriorly with the tendons of
infraspinatus and teres minor. All these blend with
the capsule towards their insertion.
Two defects in the fibrous capsule; superiorly for the
tendon of biceps. Anteriorly there is a defect beneath
the subscapularis tendon.
The inferior extension of the capsule is closely
related to the axillary nerve at the surgical neck and
this nerve is at risk in anteroinferior dislocations. It
also means that proximally sited osteomyelitis may
progress to septic arthritis.
Movements and muscles
Flexion Anterior part of deltoid
Pectoralis major
Biceps
Coracobrachialis
Extension Posterior deltoid
Teres major
Latissimus dorsi
Adduction Pectoralis major
Latissimus dorsi
Teres major
Coracobrachialis
Abduction Mid deltoid
Supraspinatus
Medial rotation Subscapularis
Anterior deltoid
Teres major
Latissimus dorsi
Lateral rotation Posterior deltoid
Infraspinatus
Teres minor
Important anatomical relations
Anteriorly Brachial plexus
Axillary artery and vein
Posterior Suprascapular nerve
Suprascapular vessels
Inferior Axillary nerve
Circumflex humeral vessels
hich of the following nerves is not contained within the
posterior triangle of the neck?
A. Accessory nerve
B. Phrenic nerve
C. Greater auricular nerve
D. Ansa cervicalis
E. Lesser occiptal nerve
Next question
Theme from September 2012 Exam
Ansa cervicalis is a content of the anterior triangle of the
neck.
Posterior triangle of the neck
Boundaries
Apex Sternocleidomastoid and the Trapezius muscles at the Occipital
bone
Anterior Posterior border of the Sternocleidomastoid
Posterior Anterior border of the Trapezius
Base Middle third of the clavicle
Image sourced from Wikipedia
Contents
Nerves Accessory nerve
Phrenic nerve
Three trunks of the brachial plexus
Branches of the cervical plexus: Supraclavicular nerve,
transverse cervical nerve, great auricular nerve, lesser
occipital nerve
Vessels External jugular vein
Subclavian artery
Muscles Inferior belly of omohyoid
Scalene
Lymph
nodes
Supraclavicular
Occipital
A 73 year old lady suffers a fracture at the surgical neck of
the humerus. The decision is made to operate. There are
difficulties in reducing the fracture and a vessel lying
posterior to the surgical neck is injured. Which of the
following is this vessel most likely to be?
A. Axillary artery
B. Brachial artery
C. Thoracoacromial artery
D. Transverse scapular artery
E. Posterior circumflex humeral artery
Next question
The circumflex humeral arteries lie at the surgical neck
and is this scenario the posterior circumflex is likely to be
injured. The thoracoacromial and transverse scapular
arteries lie more superomedially. The posterior circumflex
humeral artery is a branch of the axillary artery.
Shoulder joint
Shallow synovial ball and socket type of joint.
It is an inherently unstable joint, but is capable to a
wide range of movement.
Stability is provided by muscles of the rotator cuff that
pass from the scapula to insert in the greater
tuberosity (all except sub scapularis-lesser
tuberosity).
Glenoid labrum
Fibrocartilaginous rim attached to the free edge of
the glenoid cavity
Tendon of the long head of biceps arises from within
the joint from the supraglenoid tubercle, and is fused
at this point to the labrum.
The long head of triceps attaches to the infraglenoid
tubercle
Fibrous capsule
Attaches to the scapula external to the glenoid
labrum and to the labrum itself (postero-superiorly)
Attaches to the humerus at the level of the
anatomical neck superiorly and the surgical neck
inferiorly
Anteriorly the capsule is in contact with the tendon of
subscapularis, superiorly with the supraspinatus
tendon, and posteriorly with the tendons of
infraspinatus and teres minor. All these blend with
the capsule towards their insertion.
Two defects in the fibrous capsule; superiorly for the
tendon of biceps. Anteriorly there is a defect beneath
the subscapularis tendon.
The inferior extension of the capsule is closely
related to the axillary nerve at the surgical neck and
this nerve is at risk in anteroinferior dislocations. It
also means that proximally sited osteomyelitis may
progress to septic arthritis.
Movements and muscles
Flexion Anterior part of deltoid
Pectoralis major
Biceps
Coracobrachialis
Extension Posterior deltoid
Teres major
Latissimus dorsi
Adduction Pectoralis major
Latissimus dorsi
Teres major
Coracobrachialis
Abduction Mid deltoid
Supraspinatus
Medial rotation Subscapularis
Anterior deltoid
Teres major
Latissimus dorsi
Lateral rotation Posterior deltoid
Infraspinatus
Teres minor
Important anatomical relations
Anteriorly Brachial plexus
Axillary artery and vein
Posterior Suprascapular nerve
Suprascapular vessels
Inferior Axillary nerve
Circumflex humeral vessels
Which of the structures listed below lies posterior to the
carotid sheath at the level of the 6th cervical vertebra?
A. Hypoglossal nerve
B. Vagus nerve
C. Cervical sympathetic chain
D. Ansa cervicalis
E. Glossopharyngeal nerve
Next question
The carotid sheath is crossed anteriorly by the
hypoglossal nerves and the ansa cervicalis. The vagus
lies within it. The cervical sympathetic chain lies
posteriorly between the sheath and the prevertebral
fascia.
Common carotid artery
The right common carotid artery arises at the bifurcation of
the brachiocephalic trunk, the left common carotid arises
from the arch of the aorta. Both terminate at the level of
the upper border of the thyroid cartilage (the lower border
of the third cervical vertebra) by dividing into the internal
and external carotid arteries.
Left common carotid artery
This vessel arises immediately to the left and slightly
behind the origin of the brachiocephalic trunk. Its thoracic
portion is 2.5- 3.5 cm in length and runs superolaterally to
the sternoclavicular joint.
In the thorax
The vessel is in contact, from below upwards, with the
trachea, left recurrent laryngeal nerve, left margin of the
oesophagus. Anteriorly the left brachiocephalic vein runs
across the artery, and the cardiac branches from the left
vagus descend in front of it. These structures together
with the thymus and the anterior margins of the left lung
and pleura separate the artery from the manubrium.
In the neck
The artery runs superiorly deep to sternocleidomastoid
and then enters the anterior triangle. At this point it lies
within the carotid sheath with the vagus nerve and the
internal jugular vein. Posteriorly the sympathetic trunk lies
between the vessel and the prevertebral fascia. At the
level of C7 the vertebral artery and thoracic duct lie behind
it. The anterior tubercle of C6 transverse process is
prominent and the artery can be compressed against this
structure (it corresponds to the level of the cricoid).
Anteriorly at C6 the omohyoid muscle passes superficial
to the artery.
Within the carotid sheath the jugular vein lies lateral to the
artery.
Right common carotid artery
The right common carotid arises from the brachiocephalic
artery. The right common carotid artery corresponds with
the cervical portion of the left common carotid, except that
there is no thoracic duct on the right. The oesophagus is
less closely related to the right carotid than the left.
Summary points about the carotid anatomy
Path
Passes behind the sternoclavicular joint (12% patients
above this level) to the upper border of the thyroid
cartilage, to divide into the external (ECA) and internal
carotid arteries (ICA).
Relations
Level of 6th cervical vertebra crossed by omohyoid
Then passes deep to the thyrohyoid, sternohyoid,
sternomastoid muscles.
Passes behind the carotid tubercle (transverse
process 6th cervical vertebra)-NB compression here
stops haemorrhage.
The inferior thyroid artery passes posterior to the
common carotid artery.
Then : Left common carotid artery crossed by
thoracic duct, Right common carotid artery crossed
by recurrent laryngeal nerve
Image sourced from Wikipedia
A 45 year old man presents with a lipoma located
posterior to the posterior border of the
sternocleidomastoid muscle, approximately 4cm superior
to the middle third of the clavicle. During surgical excision
of the lesion troublesome bleeding is encountered. Which
of the following is the most likely source?
A. Internal jugular vein
B. External jugular vein
C. Common carotid artery
D. Vertebral artery
E. Second part of the subclavian artery
Next question
The external jugular vein runs obliquely in the superficial
fascia of the posterior triangle. It drains into the subclavian
vein. During surgical exploration of this area the external
jugular vein may be injured and troublesome bleeding may
result. The internal jugular vein and carotid arteries are
located in the anterior triangle. The third, and not the
second, part of the subclavian artery is also a content of
the posterior triangle
Posterior triangle of the neck
Boundaries
Apex Sternocleidomastoid and the Trapezius muscles at the Occipital
bone
Anterior Posterior border of the Sternocleidomastoid
Posterior Anterior border of the Trapezius
Base Middle third of the clavicle
Image sourced from Wikipedia
Contents
Nerves Accessory nerve
Phrenic nerve
Three trunks of the brachial plexus
Branches of the cervical plexus: Supraclavicular nerve,
transverse cervical nerve, great auricular nerve, lesser
occipital nerve
Vessels External jugular vein
Subclavian artery
Muscles Inferior belly of omohyoid
Scalene
Lymph
nodes
Supraclavicular
Occipital
Which of the following upper limb muscles is not innervated by the
radial nerve?
A. Extensor carpi ulnaris
B. Abductor digit minimi
C. Anconeus
D. Supinator
E. Brachioradialis
Next question
Mnemonic for radial nerve muscles: BEST
B rachioradialis
E xtensors
S upinator
T riceps
Abductor digiti minimi is innervated by the ulnar nerve.
Radial nerve
Continuation of posterior cord of the brachial plexus (root values C5
to T1)
Path
In the axilla: lies posterior to the axillary artery on
subscapularis, latissimus dorsi and teres major.
Enters the arm between the brachial artery and the long head
of triceps (medial to humerus).
Spirals around the posterior surface of the humerus in the
groove for the radial nerve.
At the distal third of the lateral border of the humerus it then
pierces the intermuscular septum and descends in front of the
lateral epicondyle.
At the lateral epicondyle it lies deeply between brachialis and
brachioradialis where it then divides into a superficial and deep
terminal branch.
Deep branch crosses the supinator to become the posterior
interosseous nerve.
In the image below the relationships of the radial nerve can be
appreciated
Image sourced from Wikipedia
Regions innervated
Motor (main
nerve)
Triceps
Anconeus
Brachioradialis
Extensor carpi radialis
Motor (posterior
interosseous
branch
Extensor carpi ulnaris
Extensor digitorum
Extensor indicis
Extensor digiti minimi
Extensor pollicis longus and brevis
Abductor pollicis longus
Sensory The area of skin supplying the proximal phalanges on
the dorsal aspect of the hand is supplied by the radial
nerve (this does not apply to the little finger and part
of the ring finger)
Muscular innervation and effect of denervation
Anatomical
location
Muscle affected Effect of paralysis
Shoulder Long head of triceps Minor effects on shoulder
stability in abduction
Arm Triceps Loss of elbow extension
Forearm Supinator
Brachioradialis
Extensor carpi radialis
longus and brevis
Weakening of supination of
prone hand and elbow flexion in
mid prone position
The cutaneous sensation of the upper limb- illustrating the
contribution of the radial nerve
Which of the following forms the floor of the anatomical snuffbox?
A. Radial artery
B. Cephalic vein
C. Extensor pollicis brevis
D. Scaphoid bone
E. Cutaneous branch of the radial nerve
Next question
The scaphoid bone forms the floor of the anatomical snuffbox. The
cutaneous branch of the radial nerve is much more superficially and
proximally located.
Anatomical snuffbox
Posterior border Tendon of extensor pollicis longus
Anterior border Tendons of extensor pollicis brevis and abductor pollicis longus
Proximal border Styloid process of the radius
Distal border Apex of snuffbox triangle
Floor Trapezium and scaphoid
Content Radial artery
Image showing the anatomical snuffbox
A 32 year old lady complains of carpal tunnel syndrome. The carpal
tunnel is explored surgically. Which of the following structures will lie
in closest proximity to the hamate bone within the carpal tunnel?
A. The tendon of abductor pollicis longus
B. The tendons of flexor digitorum profundus
C. The tendons of flexor carpi radialis longus
D. Median nerve
E. Radial artery
Next question
The carpal tunnel contains nine flexor tendons:
Flexor digitorum profundus
Flexor digitorum superficialis
Flexor pollicis longus
The tendon of flexor digitorum profundus lies deepest in the tunnel
and will thus lie nearest to the hamate bone.
Carpal bones
Diagrammatic image of carpal bones
Image sourced from Wikipedia
Key to image
A Scaphoid
B Lunate
C Triquetrum
D Pisiform
E Trapezium
F Trapezoid
G Capitate
H Hamate
1 Radius
2 Ulna
3 Metacarpals
No tendons attach to: Scaphoid, lunate, triquetrum (stabilised
by ligaments)
A 45 year man presents with hand weakness. He is given a piece of
paper to hold between his thumb and index finger. When the paper is
pulled, the patient has difficulty maintaining a grip. Grip pressure is
maintained by flexing the thumb at the interphalangeal joint. What is
the most likely nerve lesion?
A. Posterior interosseous nerve
B. Deep branch of ulnar nerve
C. Anterior interosseous nerve
D. Superficial branch of the ulnar nerve
E. Radial nerve
Next question
Theme from January 2012 exam
This is a description of Froment's sign, which tests for ulnar nerve
palsy. It mainly tests for the function of adductor pollicis. This is
supplied by the deep branch of the ulnar nerve. Remember the
anterior interosseous branch, which innervates the flexor pollicis
longus (hence causing flexion of the thumb IP joint), branches off
more proximally to the wrist.
Ulnar nerve
Origin
C8, T1
Supplies (no muscles in the upper arm)
Flexor carpi ulnaris
Flexor digitorum profundus
Flexor digiti minimi
Abductor digiti minimi
Opponens digiti minimi
Adductor pollicis
Interossei muscle
Third and fourth lumbricals
Palmaris brevis
Path
Posteromedial aspect of ulna to flexor compartment of forearm,
then along the ulnar. Passes beneath the flexor carpi ulnaris
muscle, then superficially through the flexor retinaculum into
the palm of the hand.
Image sourced from Wikipedia
Branches
Branch Supplies
Articular branch Flexor carpi ulnaris
Medial half of the flexor digitorum profundus
Palmar cutaneous branch (Arises near the
middle of the forearm)
Skin on the medial part of the palm
Dorsal cutaneous branch Dorsal surface of the medial part of the hand
Superficial branch Cutaneous fibres to the anterior surfaces of the
medial one and one-half digits
Deep branch Hypothenar muscles
All the interosseous muscles
Third and fourth lumbricals
Adductor pollicis
Medial head of the flexor pollicis brevis
Effects of injury
Damage at the wrist Wasting and paralysis of intrinsic hand muscles (claw hand)
Wasting and paralysis of hypothenar muscles
Loss of sensation medial 1 and half fingers
Damage at the
elbow
Radial deviation of the wrist
Clawing less in 3rd and 4th digits
A 10 year old by falls out of a tree has suffers a supracondylar
fracture. He complains of a painful elbow and forearm. There is an
obvious loss of pincer movement involving the thumb and index
finger with minimal loss of sensation. The most likely nerve injury is
to the:
A. Ulnar nerve
B. Radial nerve
C. Anterior interosseous nerve
D. Axillary nerve damage
E. Median nerve damage above the elbow
Next question
The anterior interosseous nerve is a motor branch of the median
nerve just below the elbow. When damaged it classically causes:
Pain in the forearm
Loss of pincer movement of the thumb and index finger
(innervates the long flexor muscles of flexor pollicis longus &
flexor digitorum profundus of the index and middle finger)
Minimal loss of sensation due to lack of a cutaneous branch
Median nerve
The median nerve is formed by the union of a lateral and medial root
respectively from the lateral (C5,6,7) and medial (C8 and T1) cords of
the brachial plexus; the medial root passes anterior to the third part of
the axillary artery. The nerve descends lateral to the brachial artery,
crosses to its medial side (usually passing anterior to the artery). It
passes deep to the bicipital aponeurosis and the median cubital vein
at the elbow.
It passes between the two heads of the pronator teres muscle, and
runs on the deep surface of flexor digitorum superficialis (within its
fascial sheath).
Near the wrist it becomes superficial between the tendons of flexor
digitorum superficialis and flexor carpi radialis, deep to palmaris
longus tendon. It passes deep to the flexor retinaculum to enter the
palm, but lies anterior to the long flexor tendons within the carpal
tunnel.
Branches
Region Branch
Upper arm No branches, although the nerve commonly communicates with the
musculocutaneous nerve
Forearm Pronator teres
Flexor carpi radialis
Palmaris longus
Flexor digitorum superficialis
Flexor pollicis longus
Flexor digitorum profundus (only the radial half)
Distal
forearm
Palmar cutaneous branch
Hand
(Motor)
Motor supply (LOAF)
Lateral 2 lumbricals
Opponens pollicis
Abductor pollicis brevis
Flexor pollicis brevis
Hand
(Sensory)
Over thumb and lateral 2 ½ fingers
On the palmar aspect this projects proximally, on the dorsal aspect only
the distal regions are innervated with the radial nerve providing the
more proximal cutaneous innervation.
Patterns of damage
Damage at wrist
e.g. carpal tunnel syndrome
paralysis and wasting of thenar eminence muscles and
opponens pollicis (ape hand deformity)
sensory loss to palmar aspect of lateral (radial) 2 ½ fingers
Damage at elbow, as above plus:
unable to pronate forearm
weak wrist flexion
ulnar deviation of wrist
Anterior interosseous nerve (branch of median nerve)
leaves just below the elbow
results in loss of pronation of forearm and weakness of long
flexors of thumb and index finger
Topography of the median nerve
Image sourced from Wikipedia
A 32 year old attends neurology clinic complaining of tingling in his
hand. He has radial deviation of his wrist and there is mild clawing of
his fingers, with the 3rd and 4th digits being relatively spared. What is
the most likely lesion?
A. Ulnar nerve damage at the wrist
B. Ulnar nerve damage at the elbow
C. Radial nerve damage at the elbow
D. Median nerve damage at the wrist
E. Median nerve damage at the elbow
Next question
At the elbow the ulnar nerve lesion affects the flexor carpi ulnaris and
flexor digitorum profundus.
Ulnar nerve
Origin
C8, T1
Supplies (no muscles in the upper arm)
Flexor carpi ulnaris
Flexor digitorum profundus
Flexor digiti minimi
Abductor digiti minimi
Opponens digiti minimi
Adductor pollicis
Interossei muscle
Third and fourth lumbricals
Palmaris brevis
Path
Posteromedial aspect of ulna to flexor compartment of forearm,
then along the ulnar. Passes beneath the flexor carpi ulnaris
muscle, then superficially through the flexor retinaculum into
the palm of the hand.
Image sourced from Wikipedia
Branches
Branch Supplies
Articular branch Flexor carpi ulnaris
Medial half of the flexor digitorum profundus
Palmar cutaneous branch (Arises near the
middle of the forearm)
Skin on the medial part of the palm
Dorsal cutaneous branch Dorsal surface of the medial part of the hand
Superficial branch Cutaneous fibres to the anterior surfaces of the
medial one and one-half digits
Deep branch Hypothenar muscles
All the interosseous muscles
Third and fourth lumbricals
Adductor pollicis
Medial head of the flexor pollicis brevis
Effects of injury
Damage at the wrist Wasting and paralysis of intrinsic hand muscles (claw hand)
Wasting and paralysis of hypothenar muscles
Loss of sensation medial 1 and half fingers
Damage at the
elbow
Radial deviation of the wrist
Clawing less in 3rd and 4th digits
A 23 year old man is involved in a fight and is stabbed in his upper
arm. The ulnar nerve is transected. Which of the following muscles
will not demonstrate compromised function as a result?
A. Flexor carpi ulnaris
B. Medial half of flexor digitorum profundus
C. Palmaris brevis
D. Hypothenar muscles
E. Pronator teres
Next question
M edial lumbricals
A dductor pollicis
F lexor digitorum profundus/Flexor digiti minimi
I nterossei
A bductor digiti minimi and opponens
Innervates all intrinsic muscles of the hand (EXCEPT 2: thenar muscles & first
two lumbricals - supplied by median nerve)
Pronator teres is innervated by the median nerve. Palmaris brevis is
innervated by the ulnar nerve
Ulnar nerve
Origin
C8, T1
Supplies (no muscles in the upper arm)
Flexor carpi ulnaris
Flexor digitorum profundus
Flexor digiti minimi
Abductor digiti minimi
Opponens digiti minimi
Adductor pollicis
Interossei muscle
Third and fourth lumbricals
Palmaris brevis
Path
Posteromedial aspect of ulna to flexor compartment of forearm,
then along the ulnar. Passes beneath the flexor carpi ulnaris
muscle, then superficially through the flexor retinaculum into
the palm of the hand.
Image sourced from Wikipedia
Branches
Branch Supplies
Articular branch Flexor carpi ulnaris
Medial half of the flexor digitorum profundus
Palmar cutaneous branch (Arises near the
middle of the forearm)
Skin on the medial part of the palm
Dorsal cutaneous branch Dorsal surface of the medial part of the hand
Superficial branch Cutaneous fibres to the anterior surfaces of the
medial one and one-half digits
Deep branch Hypothenar muscles
All the interosseous muscles
Third and fourth lumbricals
Adductor pollicis
Medial head of the flexor pollicis brevis
Effects of injury
Damage at the wrist Wasting and paralysis of intrinsic hand muscles (claw hand)
Wasting and paralysis of hypothenar muscles
Loss of sensation medial 1 and half fingers
Damage at the
elbow
Radial deviation of the wrist
Clawing less in 3rd and 4th digits
Which of the structures listed below overlies the cephalic vein?
A. Extensor retinaculum
B. Bicipital aponeurosis
C. Biceps muscle
D. Antebrachial fascia
E. None of the above
Next question
The cephalic vein is superficially located in the upper limb and
overlies most the fascial planes. It pierces the coracoid membrane
(continuation of the clavipectoral fascia) to terminate in the axillary
vein. It lies anterolaterally to biceps.
Cephalic vein
Path
Dorsal venous arch drains laterally into the cephalic vein
Crosses the anatomical snuffbox and travels laterally up the
arm
At the antecubital fossa connected to the basilic vein by the
median cubital vein
Pierces deep fascia of deltopectoral groove to join axillary vein
A 22 year old man is involved in a fight. He sustains a laceration to
the posterior aspect of his wrist. In the emergency department the
wound is explored and the laceration is found to be transversely
orientated and overlies the region of the extensor retinaculum, which
is intact. Which of the following structures is least likely to be injured
in this scenario?
A. Dorsal cutaneous branch of the ulnar nerve
B. Tendon of extensor indicis
C. Basilic vein
D. Superficial branch of the radial nerve
E. Cephalic vein
Next question
The extensor retinaculum attaches to the radius proximal to the
styloid, thereafter it runs obliquely and distally to wind around the
ulnar styloid (but does not attach to it). The extensor tendons lie deep
to the extensor retinaculum and would therefore be less susceptible
to injury than the superficial structures.
Extensor retinaculum
The extensor rentinaculum is a thickening of the deep fascia that
stretches across the back of the wrist and holds the long extensor
tendons in position.
Its attachments are:
The pisiform and hook of hamate medially
The end of the radius laterally
Structures related to the extensor retinaculum
Structures superficial to the
retinaculum
Basilic vein
Dorsal cutaneous branch of the ulnar nerve
Cephalic vein
Superficial branch of the radial nerve
Structures passing deep to the
extensor retinaculum
Extensor carpi ulnaris tendon
Extensor digiti minimi tendon
Extensor digitorum and extensor indicis
tendon
Extensor pollicis longus tendon
Extensor carpi radialis longus tendon
Abductor pollicis longus and extensor
pollicis brevis tendons
Beneath the extensor retinaculum fibrous septa form six
compartments that contain the extensor muscle tendons. Each
compartment has its own synovial sheath.
The radial artery
The radial artery passes between the lateral collateral ligament of the
wrist joint and the tendons of the abductor pollicis longus and
extensor pollicis brevis.
Image illustrating the topography of tendons passing under the
extensor retinaculum
A man has an incision sited than runs 8cm from the deltopectoral
groove to the midline. Which of the following is not at risk of injury?
A. Cephalic vein
B. Shoulder joint capsule
C. Axillary artery
D. Pectoralis major
E. Trunk of the brachial plexus
Next question
Theme from April 2012 Exam
This region will typically lie medial to the joint capsule. The diagram
below illustrates the plane that this would transect and as it can be
appreciated the other structures are all at risk of injury.
Image sourced from Wikipedia
Pectoralis major muscle
Origin From the medial two thirds of the clavicle, manubrium and sternocostal angle
Insertion Crest of the greater tubercle of the humerus
Nerve supply Lateral pectoral nerve
Actions Adductor and medial rotator of the humerus
heme: Nerve Injury
A. Median nerve
B. Ulnar nerve
C. Radial nerve
D. Musculocutaneous nerve
E. Axillary nerve
F. Anterior interosseous nerve
G. Posterior interosseous nerve
For each scenario please select the most likely underlying nerve injury. Each option may be used once, more than once or not at all.
171. A 19 year old student is admitted to A&E after falling off a
wall. He is unable to flex his index finger. An x-ray confirms a
supracondylar fracture.
You answered Anterior interosseous nerve
The correct answer is Median nerve
This median nerve is at risk during a supracondylar fracture.
172. A well toned weight lifter attends clinic reporting weakness of
his left arm. There is weakness of flexion and supination of
the forearm.
You answered Posterior interosseous nerve
The correct answer is Musculocutaneous nerve
Mucocutaneous nerve compression due to entrapment of the
nerve between biceps and brachialis. Elbow flexion and
supination of the arm are affected. This is a rare isolated
injury.
173. An 18 year old girl sustains an Holstein-Lewis fracture. Which
nerve is at risk?
You answered Axillary nerve
The correct answer is Radial nerve
Proximal lesions affect the triceps. Also paralysis of wrist
extensors and forearm supinators occur. Reduced sensation
of dorsoradial aspect of hand and dorsal 31/2 fingers.
Holstein-Lewis fractures are fractures of the distal humerus
with radial nerve entrapment.
A 35 year old farm labourer is injures the posterior aspect of his hand with a
mechanical scythe. He severs some of his extensor tendons in this injury. How many
tunnels lie in the extensor retinaculum that transmit the tendons of the extensor
muscles?
A. One
B. Three
C. Four
D. Five
E. Six
Next question
There are six tunnels, each lined by its own synovial sheath.
Extensor retinaculum
The extensor rentinaculum is a thickening of the deep fascia that stretches across
the back of the wrist and holds the long extensor tendons in position.
Its attachments are:
The pisiform and hook of hamate medially
The end of the radius laterally
Structures related to the extensor retinaculum
Structures superficial to the retinaculum Basilic vein
Dorsal cutaneous branch of the ulnar nerve
Cephalic vein
Superficial branch of the radial nerve
Structures passing deep to the extensor
retinaculum
Extensor carpi ulnaris tendon
Extensor digiti minimi tendon
Extensor digitorum and extensor indicis tendon
Extensor pollicis longus tendon
Extensor carpi radialis longus tendon
Abductor pollicis longus and extensor pollicis brevis
tendons
Beneath the extensor retinaculum fibrous septa form six compartments that contain
the extensor muscle tendons. Each compartment has its own synovial sheath.
The radial artery
The radial artery passes between the lateral collateral ligament of the wrist joint and
the tendons of the abductor pollicis longus and extensor pollicis brevis.
Image illustrating the topography of tendons passing under the extensor retinaculum
A 23 year old man is injured during a game of rugby. He suffers a
fracture of the distal third of his clavicle, it is a compound fracture and
there is evidence of arterial haemorrhage. Which of the following
vessels is most likely to be encountered first during subsequent
surgical exploration?
A. Posterior circumflex humeral artery
B. Axillary artery
C. Thoracoacromial artery
D. Sub scapular artery
E. Lateral thoracic artery
Next question
Similar theme in September 2011 Exam
The thoracoacromial artery arises from the second part of the axillary
artery. It is a short, wide trunk, which pierces the clavipectoral fascia,
and ends, deep to pectoralis major by dividing into four branches.
Thoracoacromial artery
The thoracoacromial artery (acromiothoracic artery; thoracic axis) is a
short trunk, which arises from the forepart of the axillary artery, its
origin being generally overlapped by the upper edge of the Pectoralis
minor.
Projecting forward to the upper border of the Pectoralis minor, it
pierces the coracoclavicular fascia and divides into four branches:
pectoral, acromial, clavicular, and deltoid.
Branch Description
Pectoral
branch
Descends between the two Pectoral muscles, and is distributed to them and to
the breast, anastomosing with the intercostal branches of the internal thoracic
artery and with the lateral thoracic.
Acromial
branch
Runs laterally over the coracoid process and under the Deltoid, to which it
gives branches; it then pierces that muscle and ends on the acromion in an
arterial network formed by branches from the suprascapular, thoracoacromial,
and posterior humeral circumflex arteries.
Clavicular
branch
Runs upwards and medially to the sternoclavicular joint, supplying this
articulation, and the Subclavius
Deltoid
branch
Arising with the acromial, it crosses over the Pectoralis minor and passes in the
same groove as the cephalic vein, between the Pectoralis major and Deltoid,
and gives branches to both muscles.
68 year old man falls onto an outstretched hand. Following the
accident he is examined in the emergency department. On palpating
his anatomical snuffbox there is tenderness noted in the base. What
is the most likely injury in this scenario?
A. Rupture of the tendon of flexor pollicis
B. Scaphoid fracture
C. Distal radius fracture
D. Rupture of flexor carpi ulnaris tendon
E. None of the above
Next question
A fall onto an outstretched hand is a common mechanism of injury for
a scaphoid fracture. This should be suspected clinically if there is
tenderness in the base of the anatomical snuffbox. A tendon rupture
would not result in bony tenderness.
Scaphoid bone
The scaphoid has a concave articular surface for the head of the
capitate and at the edge of this is a crescentic surface for the
corresponding area on the lunate.
Proximally, it has a wide convex articular surface with the radius. It
has a distally sited tubercle that can be palpated. The remaining
articular surface is to the lateral side of the tubercle. It faces laterally
and is associated with the trapezium and trapezoid bones.
The narrow strip between the radial and trapezial surfaces and the
tubercle gives rise to the radial collateral carpal ligament. The
tubercle receives part of the flexor retinaculum. This area is the only
part of the scaphoid that is available for the entry of blood vessels. It
is commonly fractured and avascular necrosis may result.
Scaphoid bone
Which of the following structures passes through the quadrangular
space near the humeral head?
A. Axillary artery
B. Radial nerve
C. Axillary nerve
D. Median nerve
E. Transverse scapular artery
Next question
The quadrangular space is bordered by the humerus laterally,
subscapularis superiorly, teres major inferiorly and the long head of
triceps medially. It lies lateral to the triangular space. It transmits the
axillary nerve and posterior circumflex humeral artery.
Image sourced from Wikipedia
Shoulder joint
Shallow synovial ball and socket type of joint.
It is an inherently unstable joint, but is capable to a wide range
of movement.
Stability is provided by muscles of the rotator cuff that pass
from the scapula to insert in the greater tuberosity (all except
sub scapularis-lesser tuberosity).
Glenoid labrum
Fibrocartilaginous rim attached to the free edge of the glenoid
cavity
Tendon of the long head of biceps arises from within the joint
from the supraglenoid tubercle, and is fused at this point to the
labrum.
The long head of triceps attaches to the infraglenoid tubercle
Fibrous capsule
Attaches to the scapula external to the glenoid labrum and to
the labrum itself (postero-superiorly)
Attaches to the humerus at the level of the anatomical neck
superiorly and the surgical neck inferiorly
Anteriorly the capsule is in contact with the tendon of
subscapularis, superiorly with the supraspinatus tendon, and
posteriorly with the tendons of infraspinatus and teres minor.
All these blend with the capsule towards their insertion.
Two defects in the fibrous capsule; superiorly for the tendon of
biceps. Anteriorly there is a defect beneath the subscapularis
tendon.
The inferior extension of the capsule is closely related to the
axillary nerve at the surgical neck and this nerve is at risk in
anteroinferior dislocations. It also means that proximally sited
osteomyelitis may progress to septic arthritis.
Movements and muscles
Flexion Anterior part of deltoid
Pectoralis major
Biceps
Coracobrachialis
Extension Posterior deltoid
Teres major
Latissimus dorsi
Adduction Pectoralis major
Latissimus dorsi
Teres major
Coracobrachialis
Abduction Mid deltoid
Supraspinatus
Medial rotation Subscapularis
Anterior deltoid
Teres major
Latissimus dorsi
Lateral rotation Posterior deltoid
Infraspinatus
Teres minor
Important anatomical relations
Anteriorly Brachial plexus
Axillary artery and vein
Posterior Suprascapular nerve
Suprascapular vessels
Inferior Axillary nerve
Circumflex humeral vessels
Which of the following structures separates the ulnar artery from the
median nerve?
A. Brachioradialis
B. Pronator teres
C. Tendon of biceps brachii
D. Flexor carpi ulnaris
E. Brachialis
Next question
It lies deep to pronator teres and this separates it from the median
nerve.
Ulnar artery
Path
Starts: middle of antecubital fossa
Passes obliquely downward, reaching the ulnar side of the
forearm at a point about midway between the elbow and the
wrist. It follows the ulnar border to the wrist, crossing over the
flexor retinaculum. It then divides into the superficial and deep
volar arches.
Relations
Deep to- Pronator teres, Flexor carpi radialis, Palmaris longus
Lies on- Brachialis and Flexor digitorum profundus
Superficial to the flexor retinaculum at the wrist
The median nerve is in relation with the medial side of the artery for
about 2.5 cm. And then crosses the vessel, being separated from it
by the ulnar head of the Pronator teres
The ulnar nerve lies medially to the lower two-thirds of the artery
Branch
Anterior interosseous artery
A 32 year old motorcyclist is involved in a road traffic accident. His
humerus is fractured and severely displaced. At the time of surgical
repair the surgeon notes that the radial nerve has been injured.
Which of the following muscles is least likely to be affected by an
injury at this site?
A. Extensor carpi radialis brevis
B. Brachioradialis
C. Abductor pollicis longus
D. Extensor pollicis brevis
E. None of the above
Next question
Muscles supplied by the radial nerve
BEST
Brachioradialis
Extensors
Supinator
Triceps
The radial nerve supplies the extensor muscles, abductor pollicis
longus and extensor pollicis brevis (the latter two being innervated by
the posterior interosseous branch of the radial nerve).
Radial nerve
Continuation of posterior cord of the brachial plexus (root values C5
to T1)
Path
In the axilla: lies posterior to the axillary artery on
subscapularis, latissimus dorsi and teres major.
Enters the arm between the brachial artery and the long head
of triceps (medial to humerus).
Spirals around the posterior surface of the humerus in the
groove for the radial nerve.
At the distal third of the lateral border of the humerus it then
pierces the intermuscular septum and descends in front of the
lateral epicondyle.
At the lateral epicondyle it lies deeply between brachialis and
brachioradialis where it then divides into a superficial and deep
terminal branch.
Deep branch crosses the supinator to become the posterior
interosseous nerve.
In the image below the relationships of the radial nerve can be
appreciated
Image sourced from Wikipedia
Regions innervated
Motor (main
nerve)
Triceps
Anconeus
Brachioradialis
Extensor carpi radialis
Motor (posterior
interosseous
branch
Extensor carpi ulnaris
Extensor digitorum
Extensor indicis
Extensor digiti minimi
Extensor pollicis longus and brevis
Abductor pollicis longus
Sensory The area of skin supplying the proximal phalanges on
the dorsal aspect of the hand is supplied by the radial
nerve (this does not apply to the little finger and part
of the ring finger)
Muscular innervation and effect of denervation
Anatomical
location
Muscle affected Effect of paralysis
Shoulder Long head of triceps Minor effects on shoulder
stability in abduction
Arm Triceps Loss of elbow extension
Forearm Supinator
Brachioradialis
Extensor carpi radialis
longus and brevis
Weakening of supination of
prone hand and elbow flexion in
mid prone position
The cutaneous sensation of the upper limb- illustrating the
contribution of the radial nerve
Image sourced from Wikipedia
Which muscle is responsible for causing flexion of the
interphalangeal joint of the thumb?
A. Flexor pollicis longus
B. Flexor pollicis brevis
C. Flexor digitorum superficialis
D. Flexor digitorum profundus
E. Adductor pollicis
Next question
There are 8 muscles:
1. Two flexors (flexor pollicis brevis and flexor pollicis longus)
2. Two extensors (extensor pollicis brevis and longus)
3. Two abductors (abductor pollicis brevis and longus)
4. One adductor (adductor pollicis)
5. One muscle that opposes the thumb by rotating the CMC joint
(opponens pollicis).
Flexor and extensor longus insert on the distal phalanx moving both
the MCP and IP joints.
Hand
Anatomy of the hand
Bones 8 Carpal bones
5 Metacarpals
14 phalanges
Intrinsic Muscles 7 Interossei - Supplied by ulnar nerve
3 palmar-adduct fingers
4 dorsal- abduct fingers
Intrinsic muscles Lumbricals
Flex MCPJ and extend the IPJ.
Origin deep flexor tendon and insertion dorsal extensor hood
mechanism.
Innervation: 1st and 2nd- median nerve, 3rd and 4th- deep
branch of the ulnar nerve.
Thenar eminence Abductor pollicis brevis
Opponens pollicis
Flexor pollicis brevis
Hypothenar
eminence
Opponens digiti minimi
Flexor digiti minimi brevis
Abductor digiti minimi
Image sourced from Wikipedia
n 18 year old man is stabbed in the axilla during a fight. His axillary
artery is lacerated and repaired. However, the surgeon neglects to
repair an associated injury to the upper trunk of the brachial plexus.
Which of the following muscles is least likely to demonstrate impaired
function as a result?
A. Palmar interossei
B. Infraspinatus
C. Brachialis
D. Supinator brevis
E. None of the above
Next question
The palmar interossei are supplied by the ulnar nerve. Which lies
inferiorly and is therefore less likely to be injured.
Brachial plexus
Origin Anterior rami of C5 to T1
Sections of the
plexus
Roots, trunks, divisions, cords, branches
Mnemonic:Real Teenagers Drink Cold Beer
Roots Located in the posterior triangle
Pass between scalenus anterior and medius
Trunks Located posterior to middle third of clavicle
Upper and middle trunks related superiorly to the subclavian
artery
Lower trunk passes over 1st rib posterior to the subclavian
artery
Divisions Apex of axilla
Cords Related to axillary artery
Diagram illustrating the branches of the brachial plexus
Image sourced from Wikipedia
Cutaneous sensation of the upper limb
Image sourced from Wikipedia
23 year old man is involved in a fight, during the dispute he sustains
a laceration to the posterior aspect of his right arm, approximately
2cm proximal to the olecranon process. On assessment in the
emergency department he is unable to extend his elbow joint. Which
of the following tendons is most likely to have been cut?
A. Triceps
B. Pronator teres
C. Brachioradialis
D. Brachialis
E. Biceps
Next question
Theme from 2009 Exam
The triceps muscle extends the elbow joint. The other muscles listed
all produce flexion of the elbow joint.
Triceps
Origin Long head- infraglenoid tubercle of the scapula.
Lateral head- dorsal surface of the humerus, lateral and proximal to
the groove of the radial nerve
Medial head- posterior surface of the humerus on the inferomedial
side of the radial groove and both of the intermuscular septae
Insertion Olecranon process of the ulna. Here the olecranon bursa is between
the triceps tendon and olecranon.
Some fibres insert to the deep fascia of the forearm, posterior capsule
of the elbow (preventing the capsule from being trapped between
olecranon and olecranon fossa during extension)
Innervation Radial nerve
Blood
supply
Profunda brachii artery
Action Elbow extension. The long head can adduct the humerus and and extend it
from a flexed position
Relations The radial nerve and profunda brachii vessels lie between the lateral and
medial heads
Which of the following muscles does not attach to the radius?
A. Pronator quadratus
B. Biceps
C. Brachioradialis
D. Supinator
E. Brachialis
Next question
The brachialis muscle inserts into the ulna. The other muscles are all
inserted onto the radius.
Radius
Bone of the forearm extending from the lateral side of the
elbow to the thumb side of the wrist
Upper end
Articular cartilage- covers medial > lateral side
Articulates with radial notch of the ulna by the annular ligament
Muscle attachment- biceps brachii at the tuberosity
Shaft
Muscle attachment-
Upper third of the body Supinator, Flexor digitorum superficialis,
Flexor pollicis longus
Middle third of the body Pronator teres
Lower quarter of the body Pronator quadratus , tendon of supinator
longus
Lower end
Quadrilateral
Anterior surface- capsule of wrist joint
Medial surface- head of ulna
Lateral surface- ends in the styloid process
Posterior surface: 3 grooves containing:
1. Tendons of extensor carpi radialis longus and brevis
2. Tendon of extensor pollicis longus
3. Tendon of extensor indicis
Which of the following is not an intrinsic muscle of the hand?
A. Opponens pollicis
B. Palmaris longus
C. Flexor pollicis brevis
D. Flexor digiti minimi brevis
E. Opponens digiti minimi
Next question
Mnemonic for intrinsic hand muscles
'A OF A OF A'
A bductor pollicis brevis
O pponens pollicis
F lexor pollicis brevis
A dductor pollicis (thenar muscles)
O pponens digiti minimi
F lexor digiti minimi brevis
A bductor digiti minimi (hypothenar muscles)
Palmaris longus originates in the forearm.
Hand
Anatomy of the hand
Bones 8 Carpal bones
5 Metacarpals
14 phalanges
Intrinsic Muscles 7 Interossei - Supplied by ulnar nerve
3 palmar-adduct fingers
4 dorsal- abduct fingers
Intrinsic muscles Lumbricals
Flex MCPJ and extend the IPJ.
Origin deep flexor tendon and insertion dorsal extensor hood
mechanism.
Innervation: 1st and 2nd- median nerve, 3rd and 4th- deep
branch of the ulnar nerve.
Thenar eminence Abductor pollicis brevis
Opponens pollicis
Flexor pollicis brevis
Hypothenar
eminence
Opponens digiti minimi
Flexor digiti minimi brevis
Abductor digiti minimi
Image sourced from Wikipedia
A 28 year old man lacerates the posterolateral aspect of his wrist with
a knife in an attempted suicide. On arrival in the emergency
department the wound is inspected and found to be located over the
lateral aspect of the extensor retinaculum (which is intact). Which of
the following structures is at greatest risk of injury?
A. Superficial branch of the radial nerve
B. Radial artery
C. Dorsal branch of the ulnar nerve
D. Tendon of extensor carpi radialis brevis
E. Tendon of extensor digiti minimi
Next question
The superficial branch of the radial nerve passes superior to the
extensor retinaculum in the position of this laceration and is at
greatest risk of injury. The dorsal branch of the ulnar nerve and artery
also pass superior to the extensor retinaculum n but are located
medially.
Extensor retinaculum
The extensor rentinaculum is a thickening of the deep fascia that
stretches across the back of the wrist and holds the long extensor
tendons in position.
Its attachments are:
The pisiform and hook of hamate medially
The end of the radius laterally
Structures related to the extensor retinaculum
Structures superficial to the
retinaculum
Basilic vein
Dorsal cutaneous branch of the ulnar nerve
Cephalic vein
Superficial branch of the radial nerve
Structures passing deep to the
extensor retinaculum
Extensor carpi ulnaris tendon
Extensor digiti minimi tendon
Extensor digitorum and extensor indicis
tendon
Extensor pollicis longus tendon
Extensor carpi radialis longus tendon
Abductor pollicis longus and extensor
pollicis brevis tendons
Beneath the extensor retinaculum fibrous septa form six
compartments that contain the extensor muscle tendons. Each
compartment has its own synovial sheath.
The radial artery
The radial artery passes between the lateral collateral ligament of the
wrist joint and the tendons of the abductor pollicis longus and
extensor pollicis brevis.
Image illustrating the topography of tendons passing under the
extensor retinaculum
ransection of the radial nerve at the level of the axilla will result in all
of the following except:
A. Loss of elbow extension.
B. Loss of extension of the interphalangeal joints.
C. Loss of metacarpophalangeal extension.
D. Loss of triceps reflex.
E. Loss of sensation overlying the first dorsal interosseous.
Next question
These may still extend by virtue of retained lumbrical muscle
function.
Radial nerve
Continuation of posterior cord of the brachial plexus (root values C5
to T1)
Path
In the axilla: lies posterior to the axillary artery on
subscapularis, latissimus dorsi and teres major.
Enters the arm between the brachial artery and the long head
of triceps (medial to humerus).
Spirals around the posterior surface of the humerus in the
groove for the radial nerve.
At the distal third of the lateral border of the humerus it then
pierces the intermuscular septum and descends in front of the
lateral epicondyle.
At the lateral epicondyle it lies deeply between brachialis and
brachioradialis where it then divides into a superficial and deep
terminal branch.
Deep branch crosses the supinator to become the posterior
interosseous nerve.
In the image below the relationships of the radial nerve can be
appreciated
Image sourced from Wikipedia
Regions innervated
Motor (main
nerve)
Triceps
Anconeus
Brachioradialis
Extensor carpi radialis
Motor (posterior
interosseous
branch
Extensor carpi ulnaris
Extensor digitorum
Extensor indicis
Extensor digiti minimi
Extensor pollicis longus and brevis
Abductor pollicis longus
Sensory The area of skin supplying the proximal phalanges on
the dorsal aspect of the hand is supplied by the radial
nerve (this does not apply to the little finger and part
of the ring finger)
Muscular innervation and effect of denervation
Anatomical
location
Muscle affected Effect of paralysis
Shoulder Long head of triceps Minor effects on shoulder
stability in abduction
Arm Triceps Loss of elbow extension
Forearm Supinator
Brachioradialis
Extensor carpi radialis
longus and brevis
Weakening of supination of
prone hand and elbow flexion in
mid prone position
The cutaneous sensation of the upper limb- illustrating the
contribution of the radial nerve
Image sourced from Wikipedia
A. Teres major
B. Pectoralis major
C. Coracobrachialis
D. Supraspinatus
E. Latissimus dorsi
Next question
Supraspinatus is an abductor of the shoulder.
Shoulder joint
Shallow synovial ball and socket type of joint.
It is an inherently unstable joint, but is capable to a wide range
of movement.
Stability is provided by muscles of the rotator cuff that pass
from the scapula to insert in the greater tuberosity (all except
sub scapularis-lesser tuberosity).
Glenoid labrum
Fibrocartilaginous rim attached to the free edge of the glenoid
cavity
Tendon of the long head of biceps arises from within the joint
from the supraglenoid tubercle, and is fused at this point to the
labrum.
The long head of triceps attaches to the infraglenoid tubercle
Fibrous capsule
Attaches to the scapula external to the glenoid labrum and to
the labrum itself (postero-superiorly)
Attaches to the humerus at the level of the anatomical neck
superiorly and the surgical neck inferiorly
Anteriorly the capsule is in contact with the tendon of
subscapularis, superiorly with the supraspinatus tendon, and
posteriorly with the tendons of infraspinatus and teres minor.
All these blend with the capsule towards their insertion.
Two defects in the fibrous capsule; superiorly for the tendon of
biceps. Anteriorly there is a defect beneath the subscapularis
tendon.
The inferior extension of the capsule is closely related to the
axillary nerve at the surgical neck and this nerve is at risk in
anteroinferior dislocations. It also means that proximally sited
osteomyelitis may progress to septic arthritis.
Movements and muscles
Flexion Anterior part of deltoid
Pectoralis major
Biceps
Coracobrachialis
Extension Posterior deltoid
Teres major
Latissimus dorsi
Adduction Pectoralis major
Latissimus dorsi
Teres major
Coracobrachialis
Abduction Mid deltoid
Supraspinatus
Medial rotation Subscapularis
Anterior deltoid
Teres major
Latissimus dorsi
Lateral rotation Posterior deltoid
Infraspinatus
Teres minor
Important anatomical relations
Anteriorly Brachial plexus
Axillary artery and vein
Posterior Suprascapular nerve
Suprascapular vessels
Inferior Axillary nerve
Circumflex humeral vessels
low?
A. External jugular
B. Axillary
C. Internal jugular
D. Azygos
E. Brachial
Next question
Cephalic vein
Path
Dorsal venous arch drains laterally into the cephalic vein
Crosses the anatomical snuffbox and travels laterally up the
arm
At the antecubital fossa connected to the basilic vein by the
median cubital vein
Pierces deep fascia of deltopectoral groove to join axillary vein
Which of the following structures is not closely related to the
brachial artery?
A. Ulnar nerve
B. Median nerve
C. Cephalic vein
D. Long head of triceps
E. Median cubital vein
Next question
The cephalic vein lies superficially and on the contralateral side
of the arm to the brachial artery. The relation of the ulnar
nerves and others are demonstrated in the image below:
Image sourced from Wikipedia
Brachial artery
The brachial artery begins at the lower border of teres major as
a continuation of the axillary artery. It terminates in the cubital
fossa at the level of the neck of the radius by dividing into the
radial and ulnar arteries.
Relations
Posterior relations include the long head of triceps with the
radial nerve and profunda vessels intervening. Anteriorly it is
overlapped by the medial border of biceps.
It is crossed by the median nerve in the middle of the arm.
In the cubital fossa it is separated from the median cubital vein
by the bicipital aponeurosis.
The basilic vein is in contact at the most proximal aspect of the
cubital fossa and lies medially.
The following statements relating to the musculocutaneous nerve are
true except?
A. It arises from the lateral cord of the brachial plexus
B. It provides cutaneous innervation to the lateral side of the
forearm
C. If damaged then extension of the elbow joint will be impaired
D. It supplies the biceps muscle
E. It runs beneath biceps
Next question
It supplies biceps, brachialis and coracobrachialis so if damaged then
elbow flexion will be impaired.
Musculocutaneous nerve
Branch of lateral cord of brachial plexus
Path
It penetrates the Coracobrachialis muscle
Passes obliquely between the Biceps brachii and the Brachialis
to the lateral side of the arm
Above the elbow it pierces the deep fascia lateral to the tendon
of the Biceps brachii
Continues into the forearm as the lateral cutaneous nerve of
the forearm
Innervates
Coracobrachialis
Biceps brachii
Brachialis
Which ligament keeps the head of the radius connected to the radial
notch of the ulna?
A. Annular (orbicular) ligament
B. Quadrate ligament
C. Radial collateral ligament of the elbow
D. Ulnar collateral ligament
E. Radial collateral ligament
Next question
The annular ligament connects the radial head to the radial notch of
the ulna. This is illustrated below:
Image sourced from Wikipedia
Radius
Bone of the forearm extending from the lateral side of the
elbow to the thumb side of the wrist
Upper end
Articular cartilage- covers medial > lateral side
Articulates with radial notch of the ulna by the annular ligament
Muscle attachment- biceps brachii at the tuberosity
Shaft
Muscle attachment-
Upper third of the body Supinator, Flexor digitorum superficialis,
Flexor pollicis longus
Middle third of the body Pronator teres
Lower quarter of the body Pronator quadratus , tendon of supinator
longus
Lower end
Quadrilateral
Anterior surface- capsule of wrist joint
Medial surface- head of ulna
Lateral surface- ends in the styloid process
Posterior surface: 3 grooves containing:
1. Tendons of extensor carpi radialis longus and brevis
2. Tendon of extensor pollicis longus
3. Tendon of extensor indicis
Image sourced from Wikipedia
A 38 year old man presents to the clinic with shoulder weakness. On
examination he has an inability to initiate shoulder abduction. Which
of the nerves listed below is least likely to be functioning normally?
A. Suprascapular nerve
B. Medial pectoral nerve
C. Axillary nerve
D. Median nerve
E. Radial nerve
Next question
Theme from April 2012 Exam
Suprascapular nerve
The suprascapular nerve arises from the upper trunk of the brachial
plexus. It lies superior to the trunks of the brachial plexus and passes
inferolaterally parallel to them. It passes through the scapular notch,
deep to trapezius. It innervates both supraspinatus and infraspinatus
and initiates abduction of the shoulder. If damaged, patients may be
able to abduct the shoulder by leaning over the affected side and
deltoid can then continue to abduct the shoulder.
Which of the following vessels provides the greatest contribution to
the arterial supply of the breast?
A. External mammary artery
B. Thoracoacromial artery
C. Internal mammary artery
D. Lateral thoracic artery
E. Subclavian artery
Next question
60% of the arterial supply to the breast is derived from the internal
mammary artery. The external mammary and lateral thoracic arteries
also make a significant (but lesser) contribution. This is of importance
clinically in performing reduction mammoplasty procedures.
Breast
The breast itself lies on a layer of pectoral fascia and the following
muscles:
1. Pectoralis major
2. Serratus anterior
3. External oblique
Image showing the topography of the female breast
Image sourced from Wikipedia
Breast anatomy
Nerve supply Branches of intercostal nerves from T4-T6.
Arterial supply Internal mammary (thoracic) artery
External mammary artery (laterally)
Anterior intercostal arteries
Thoraco-acromial artery
Venous drainage Superficial venous plexus to sub clavian, axillary and intercostal veins.
Lymphatic
drainage
70% Axillary nodes
Internal mammary chain
Other lymphatic sites such as deep cervical and supraclavicular
fossa (later in disease)
A baby is found to have a Klumpke's palsy post delivery. Which of the
following is most likely to be present?
A. Loss of flexors of the wrist
B. Weak elbow flexion
C. Pronation of the forearm
D. Adducted shoulder
E. Shoulder medially rotated
Next question
Features of Klumpkes Paralysis
Claw hand (MCP joints extended and IP joints flexed)
Loss of sensation over medial aspect of forearm and hand
Horner's syndrome
Loss of flexors of the wrist
A C8, T1 root lesion is called Klumpke's paralysis and is caused by
delivery with the arm extended.
Brachial plexus
Origin Anterior rami of C5 to T1
Sections of the
plexus
Roots, trunks, divisions, cords, branches
Mnemonic:Real Teenagers Drink Cold Beer
Roots Located in the posterior triangle
Pass between scalenus anterior and medius
Trunks Located posterior to middle third of clavicle
Upper and middle trunks related superiorly to the subclavian
artery
Lower trunk passes over 1st rib posterior to the subclavian
artery
Divisions Apex of axilla
Cords Related to axillary artery
Diagram illustrating the branches of the brachial plexus
Image sourced from Wikipedia
Cutaneous sensation of the upper limb
ith respect to the basilic vein, which statement is false?
A. Its deep anatomical location makes it unsuitable for use as an
arteriovenous access site in fistula surgery
B. It originates from the dorsal venous network on the hand
C. It travels up the medial aspect of the forearm
D. Halfway between the shoulder and the elbow it lies deep to
muscle
E. It joins the brachial vein to form the axillary vein
Next question
It is used in arteriovenous fistula surgery during a procedure known
as a basilic vein transposition.
Basilic vein
The basilic and cephalic veins both provide the main pathways of
venous drainage for the arm and hand. It is continuous with the
palmar venous arch distally and the axillary vein proximally.
Path
Originates on the medial side of the dorsal venous network of
the hand, and passes up the forearm and arm.
Most of its course is superficial.
Near the region anterior to the cubital fossa the vein joins the
cephalic vein.
Midway up the humerus the basilic vein passes deep under the
muscles.
At the lower border of the teres major muscle, the anterior and
posterior circumflex humeral veins feed into it.
Joins the brachial veins to form the axillary vein.
A 78 year old man is lifting a heavy object when a feels a pain in his
forearm and is unable to continue. He has a swelling over his upper
forearm. An MRI scan shows a small cuff of tendon still attached to
the radial tuberosity consistent with a recent tear. Which of the
following muscles has been injured?
A. Pronator teres
B. Supinator
C. Aconeus
D. Brachioradialis
E. Biceps brachii
Next question
Biceps inserts into the radial tuberosity. Distal injuries of this muscle
are rare but are reported and are clinically more important than more
proximal ruptures.
Radius
Bone of the forearm extending from the lateral side of the
elbow to the thumb side of the wrist
Upper end
Articular cartilage- covers medial > lateral side
Articulates with radial notch of the ulna by the annular ligament
Muscle attachment- biceps brachii at the tuberosity
Shaft
Muscle attachment-
Upper third of the body Supinator, Flexor digitorum superficialis,
Flexor pollicis longus
Middle third of the body Pronator teres
Lower quarter of the body Pronator quadratus , tendon of supinator
longus
Lower end
Quadrilateral
Anterior surface- capsule of wrist joint
Medial surface- head of ulna
Lateral surface- ends in the styloid process
Posterior surface: 3 grooves containing:
1. Tendons of extensor carpi radialis longus and brevis
2. Tendon of extensor pollicis longus
3. Tendon of extensor indicis
Which of the following is a branch of the third part of the axillary
artery?
A. Superior thoracic
B. Lateral thoracic
C. Dorsal scapular
D. Thoracoacromial
E. Posterior circumflex humeral
Next question
The other branches include:
Subscapular
Anterior circumflex humeral
Axilla
Boundaries of the axilla
Medially Chest wall and Serratus anterior
Laterally Humeral head
Floor Subscapularis
Anterior aspect Lateral border of Pectoralis major
Fascia Clavipectoral fascia
Content:
Long thoracic nerve (of
Bell)
Derived from C5-C7 and passes behind the brachial plexus to
enter the axilla. It lies on the medial chest wall and supplies
serratus anterior. Its location puts it at risk during axillary
surgery and damage will lead to winging of the scapula.
Thoracodorsal nerve
and thoracodorsal trunk
Innervate and vascularise latissimus dorsi.
Axillary vein Lies at the apex of the axilla, it is the continuation of the basilic
vein. Becomes the subclavian vein at the outer border of the first
rib.
Intercostobrachial Traverse the axillary lymph nodes and are often divided during
nerves axillary surgery. They provide cutaneous sensation to the axillary
skin.
Lymph nodes The axilla is the main site of lymphatic drainage for the breast.
Theme: Nerve lesions
A. Intercostobrachial
B. Median
C. Axillary
D. Radial
E. Ulnar
F. Musculocutaneous
G. Brachial plexus upper cord
H. Brachial plexus lower cord
Please select the most likely nerve injury for the scenarios given.
Each option may be used once, more than once or not at all.
268. A 23 year old rugby player sustains a Smiths Fracture. On examination
opposition of the thumb is markedly weakened.
Median
This high velocity injury can often produce significant angulation and
displacement. Both of these may impair the function of the median
nerve with loss of function of the muscles of the thenar eminence
269. A 45 year old lady recovering from a mastectomy and axillary node
clearance notices that sensation in her armpit is impaired.
Intercostobrachial
The intercostobrachial nerves are frequently injured during axillary
dissection. These nerves traverse the axilla and supply cutaneous
sensation.
270. An 8 year old boy falls onto an outstretched hand and sustains a
supracondylar fracture. In addition to a weak radial pulse the child is
noted to have loss of pronation of the affected hand.
Median
This is a common injury in children. In this case the angulation and
displacement have resulted in median nerve injury.
Next question
Brachial plexus
Origin Anterior rami of C5 to T1
Sections of the
plexus
Roots, trunks, divisions, cords, branches
Mnemonic:Real Teenagers Drink Cold Beer
Roots Located in the posterior triangle
Pass between scalenus anterior and medius
Trunks Located posterior to middle third of clavicle
Upper and middle trunks related superiorly to the subclavian
artery
Lower trunk passes over 1st rib posterior to the subclavian
artery
Divisions Apex of axilla
Cords Related to axillary artery
Diagram illustrating the branches of the brachial plexus
Image sourced from Wikipedia
Cutaneous sensation of the upper limb
Image sourced from Wikipedia
froment's test which muscle function is tested?
A. Flexor pollicis longus
B. Adductor pollicis longus
C. Abductor pollicis brevis
D. Adductor pollicis
E. Opponens pollicis
Next question
Nerve signs
Froment's sign
Assess for ulnar nerve palsy
Adductor pollicis muscle function tested
Hold a piece of paper between their thumb and index finger.
The object is then pulled away. If ulnar nerve palsy, unable to
hold the paper and will flex the flexor pollicis longus to
compensate (flexion of thumb at interphalangeal joint).
Phalen's test
Assess carpal tunnel syndrome
More sensitive than Tinel's sign
Hold wrist in maximum flexion and the test is positive if there is
numbness in the median nerve distribution.
Tinel's sign
Assess for carpal tunnel syndrome
Tap the median nerve at the wrist and the test is positive if
there is tingling/electric-like sensations over the distribution of
the median nerve.
heme: Cutaneous innervation
A. Ulnar nerve
B. Fifth cervical spinal segment
C. Radial nerve
D. Musculocutaneous nerve
E. Median nerve
F. None of these
Please select the source of innervation for the region described.
Each option may be used once, more than once or not at all.
288. The skin on the palmar aspect of the thumb
Median nerve
The median nerve supplies cutaneous sensation to this region.
See diagram below
289. The nail bed of the index finger
You answered Radial nerve
The correct answer is Median nerve
290. The skin overlying the medial aspect of the palm
Ulnar nerve
This area is innervated by the ulnar nerve.
Next question
Brachial plexus
Origin Anterior rami of C5 to T1
Sections of the
plexus
Roots, trunks, divisions, cords, branches
Mnemonic:Real Teenagers Drink Cold Beer
Roots Located in the posterior triangle
Pass between scalenus anterior and medius
Trunks Located posterior to middle third of clavicle
Upper and middle trunks related superiorly to the subclavian
artery
Lower trunk passes over 1st rib posterior to the subclavian
artery
Divisions Apex of axilla
Cords Related to axillary artery
Diagram illustrating the branches of the brachial plexus
Image sourced from Wikipedia
Cutaneous sensation of the upper limb
From which of the following foramina does the opthalmic branch of
the trigeminal nerve exit the skull?
A. Foramen ovale
B. Foramen rotundum
C. Foramen spinosum
D. Superior orbital fissure
E. Foramen magnum
Next question
Mnemonic:
Standing Room Only -Exit of branches of trigeminal nerve from the skull
V1 -Superior orbital fissure
V2 -foramen Rotundum
V3 -foramen Ovale
The opthalmic branch of the trigeminal nerve exits the skull through
the superior orbital fissure.
Trigeminal nerve
The trigeminal nerve is the main sensory nerve of the head. In
addition to its major sensory role, it also innervates the muscles of
mastication.
Distribution of the trigeminal nerve
Sensory Scalp
Face
Oral cavity (and teeth)
Nose and sinuses
Dura mater
Motor Muscles of mastication
Mylohyoid
Anterior belly of digastric
Tensor tympani
Tensor palati
Autonomic connections (ganglia) Ciliary
Sphenopalatine
Otic
Submandibular
Path
Originates at the pons
Sensory root forms the large, crescentic trigeminal ganglion
within Meckel's cave, and contains the cell bodies of incoming
sensory nerve fibres. Here the 3 branches exit.
The motor root cell bodies are in the pons and the motor fibres
are distributed via the mandibular nerve. The motor root is not
part of the trigeminal ganglion.
Branches of the trigeminal nerve
Ophthalmic nerve Sensory only
Maxillary nerve Sensory only
Mandibular nerve Sensory and motor
Sensory
Ophthalmic Exits skull via the superior orbital fissure
Sensation of: scalp and forehead, the upper eyelid, the conjunctiva and
cornea of the eye, the nose (including the tip of the nose, except alae nasi),
the nasal mucosa, the frontal sinuses, and parts of the meninges (the dura and
blood vessels).
Maxillary
nerve
Exit skull via the foramen rotundum
Sensation: lower eyelid and cheek, the nares and upper lip, the upper teeth
and gums, the nasal mucosa, the palate and roof of the pharynx, the
maxillary, ethmoid and sphenoid sinuses, and parts of the meninges.
Mandibular
nerve
Exit skull via the foramen ovale
Sensation: lower lip, the lower teeth and gums, the chin and jaw (except the
angle of the jaw), parts of the external ear, and parts of the meninges.
Motor
Distributed via the mandibular nerve.
The following muscles of mastication are innervated:
Masseter
Temporalis
Medial pterygoid
Lateral pterygoid
Other muscles innervated include:
Tensor veli palatini
Mylohyoid
Anterior belly of digastric
Tensor tympani
Rate
question:
1
2
3
4
5
Next question
Comment on this question
42 year old lady has had an axillary node clearance for breast malignancy. Post
operatively she reports weakness of the shoulder. She is unable to push herself
forwards from a wall with the right arm and the scapula is pushed out medially from
the chest wall. What is the most likely nerve injury?
A. C5, C6
B. C8, T1
C. Axillary nerve
D. Long thoracic nerve
E. Spinal accessory nerve
Theme from January 2012 and 2009 Exam
The patient has a winged scapula caused by damage to the long thoracic nerve
(C5,6,7) during surgery. The long thoracic nerve innervates serratus anterior. Serratus
anterior causes pushing out of the scapula during a punch.
NB winging of the scapular laterally may indicate trapezius muscle weakness.
Innervated by the spinal accessory nerve.
Long thoracic nerve
Derived from ventral rami of C5, C6, and C7 (close to their emergence from
intervertebral foramina)
It runs downward and passes either anterior or posterior to the middle scalene
muscle
It reaches upper tip of serratus anterior muscle and descends on outer surface
of this muscle, giving branches into it
Winging of Scapula occurs in long thoracic nerve injury (most common) or
from spinal accessory nerve injury (which denervates the trapezius) or a dorsal
scapular nerve injury
A 36 year old male is admitted for elective surgery for a lymph node biopsy in the
supraclavicular region. Post operatively the patient has difficulty shrugging his left shoulder.
What nerve has been damaged?
A. Phrenic nerve
B. Axillary nerve
C. C5, C6 lesion
D. C8, T1 lesion
E. Accessory nerve
Theme from September 2011 Exam
The accessory nerve lies in the posterior triangle and may be injured in this region. Apart
from problems with shrugging the shoulder, he may also have difficulty lifting his arm above
his head.
Posterior triangle of the neck
Boundaries
Apex Sternocleidomastoid and the Trapezius muscles at the Occipital bone
Anterior Posterior border of the Sternocleidomastoid
Posterior Anterior border of the Trapezius
Base Middle third of the clavicle
Image sourced from Wikipedia
Contents
Nerves Accessory nerve Phrenic nerve Three trunks of the brachial plexus Branches of the cervical plexus: Supraclavicular nerve, transverse cervical
nerve, great auricular nerve, lesser occipital nerve
Vessels External jugular vein Subclavian artery
Muscles Inferior belly of omohyoid Scalene
Lymph
nodes
Supraclavicular Occipital
Which of the following muscles is supplied by the musculocutaneous nerve?
A. Brachialis
B. Latissimus dorsi
C. Flexor carpi ulnaris
D. Teres minor
E. Triceps
Mnemonic
Muscles innervated by the
musculocutaneous nerve BBC:
Biceps brachii
Brachialis
Coracobrachialis
Musculocutaneous nerve
Branch of lateral cord of brachial plexus
Path
It penetrates the Coracobrachialis muscle
Passes obliquely between the Biceps brachii and the Brachialis to the lateral
side of the arm
Above the elbow it pierces the deep fascia lateral to the tendon of the Biceps
brachii
Continues into the forearm as the lateral cutaneous nerve of the forearm
Innervates
Coracobrachialis
Biceps brachii
Brachialis
A 17 year old male presents to the clinic. He complains of difficulty using his left hand. It has
been a persistent problem since he sustained a distal humerus fracture as a child. On
examination there is diminished sensation overlying the hypothenar eminence and medial
one and half fingers. What is the most likely nerve lesion?
A. Anterior interosseous nerve
B. Posterior interosseous nerve
C. Ulnar nerve
D. Median nerve
E. Radial nerve
Theme from April 2012 Exam
This sensory deficit pattern is most consistent with ulnar nerve injury.
Image sourced from Wikipedia
Ulnar nerve
Origin
C8, T1
Supplies (no muscles in the upper arm)
Flexor carpi ulnaris Flexor digitorum profundus Flexor digiti minimi Abductor digiti minimi Opponens digiti minimi Adductor pollicis Interossei muscle Third and fourth lumbricals
Palmaris brevis
Path
Posteromedial aspect of ulna to flexor compartment of forearm, then along the ulnar. Passes beneath the flexor carpi ulnaris muscle, then superficially through the flexor retinaculum into the palm of the hand.
Image sourced from Wikipedia
Branches
Branch Supplies
Articular branch Flexor carpi ulnaris
Medial half of the flexor digitorum profundus
Palmar cutaneous branch (Arises near the Skin on the medial part of the palm
middle of the forearm)
Dorsal cutaneous branch Dorsal surface of the medial part of the hand
Superficial branch Cutaneous fibres to the anterior surfaces of the
medial one and one-half digits
Deep branch Hypothenar muscles
All the interosseous muscles
Third and fourth lumbricals
Adductor pollicis
Medial head of the flexor pollicis brevis
Effects of injury
Damage at the wrist Wasting and paralysis of intrinsic hand muscles (claw hand) Wasting and paralysis of hypothenar muscles Loss of sensation medial 1 and half fingers
Damage at the
elbow
Radial deviation of the wrist Clawing less in 3rd and 4th digits
A 72 year old male with end stage critical ischaemia is undergoing an axillo-femoral
bypass. What structure is not closely related to the axillary artery?
A. Posterior cord of the brachial plexus
B. Scalenus anterior muscle
C. Pectoralis minor muscle
D. Axillary vein
E. Lateral cord of the brachial plexus
The axillary artery is the continuation of the subclavian artery. It is surrounded by the
cords of the brachial plexus (from which they are named). The axillary vein runs
alongside the axillary artery throughout its length.
Axilla
Boundaries of the axilla
Medially Chest wall and Serratus anterior
Laterally Humeral head
Floor Subscapularis
Anterior aspect Lateral border of Pectoralis major
Fascia Clavipectoral fascia
Content:
Long thoracic nerve (of
Bell)
Derived from C5-C7 and passes behind the brachial plexus
to enter the axilla. It lies on the medial chest wall and
supplies serratus anterior. Its location puts it at risk during
axillary surgery and damage will lead to winging of the
scapula.
Thoracodorsal nerve
and thoracodorsal
trunk
Innervate and vascularise latissimus dorsi.
Axillary vein Lies at the apex of the axilla, it is the continuation of the
basilic vein. Becomes the subclavian vein at the outer
border of the first rib.
Intercostobrachial
nerves
Traverse the axillary lymph nodes and are often divided
during axillary surgery. They provide cutaneous sensation
to the axillary skin.
Lymph nodes The axilla is the main site of lymphatic drainage for the
breast.
Which of the following carpal bones is a sesamoid bone in the tendon of flexor carpi ulnaris?
A. Triquetrum
B. Lunate
C. Pisiform
D. Scaphoid
E. Capitate
This small bone has a single articular facet. It projects from the triquetral bone at the ulnar
aspect of the wrist where most regard it as a sesamoid bine lying within the tendon of flexor
carpi ulnaris.
Carpal bones
Diagrammatic image of carpal bones
Image sourced from Wikipedia
Key to image
A Scaphoid
B Lunate
C Triquetrum
D Pisiform
E Trapezium
F Trapezoid
G Capitate
H Hamate
1 Radius
2 Ulna
3 Metacarpals
No tendons attach to: Scaphoid, lunate, triquetrum (stabilised by ligaments)
A 70 year old man falls and fractures his scaphoid bone. The fracture is displaced
and the decision is made to insert a screw to fix the fracture. Which of the following
structures lies directly medial to the scaphoid?
A. Lunate
B. Pisiform
C. Trapezoid
D. Trapezium
E. None of the above
The lunate lies medially in the anatomical plane. Fractures of the scaphoid that are
associated with high velocity injuries may cause associated lunate dislocation.
Scaphoid bone
The scaphoid has a concave articular surface for the head of the capitate and at the
edge of this is a crescentic surface for the corresponding area on the lunate.
Proximally, it has a wide convex articular surface with the radius. It has a distally
sited tubercle that can be palpated. The remaining articular surface is to the lateral
side of the tubercle. It faces laterally and is associated with the trapezium and
trapezoid bones.
The narrow strip between the radial and trapezial surfaces and the tubercle gives
rise to the radial collateral carpal ligament. The tubercle receives part of the flexor
retinaculum. This area is the only part of the scaphoid that is available for the entry
of blood vessels. It is commonly fractured and avascular necrosis may result.
Scaphoid bone
Image sourced from Wikipedia
A 73 year old lady is hit by a car. She suffers a complex fracture of the distal aspect of her
humerus with associated injury to the radial nerve. Which of the following movements will
be most impaired as a result?
A. Elbow extension
B. Elbow flexion
C. Shoulder abduction
D. Wrist extension
E. None of the above
The triceps will not be affected so elbow extension will be preserved. Loss of wrist extension
will be the most obvious effect.
Radial nerve
Continuation of posterior cord of the brachial plexus (root values C5 to T1)
Path
In the axilla: lies posterior to the axillary artery on subscapularis, latissimus dorsi and teres major.
Enters the arm between the brachial artery and the long head of triceps (medial to humerus).
Spirals around the posterior surface of the humerus in the groove for the radial nerve.
At the distal third of the lateral border of the humerus it then pierces the intermuscular septum and descends in front of the lateral epicondyle.
At the lateral epicondyle it lies deeply between brachialis and brachioradialis where it then divides into a superficial and deep terminal branch.
Deep branch crosses the supinator to become the posterior interosseous nerve.
In the image below the relationships of the radial nerve can be appreciated
Image sourced from Wikipedia
Regions innervated
Motor (main nerve) Triceps Anconeus Brachioradialis Extensor carpi radialis
Motor (posterior
interosseous
branch
Extensor carpi ulnaris Extensor digitorum Extensor indicis Extensor digiti minimi Extensor pollicis longus and brevis Abductor pollicis longus
Sensory The area of skin supplying the proximal phalanges on the dorsal aspect
of the hand is supplied by the radial nerve (this does not apply to the
little finger and part of the ring finger)
Muscular innervation and effect of denervation
Anatomical
location
Muscle affected Effect of paralysis
Shoulder Long head of triceps Minor effects on shoulder stability in
abduction
Arm Triceps Loss of elbow extension
Forearm Supinator
Brachioradialis
Extensor carpi radialis
longus and brevis
Weakening of supination of prone hand and
elbow flexion in mid prone position
The cutaneous sensation of the upper limb- illustrating the contribution of the radial nerve
Image sourced from Wikipedia
An 18 year old man develops a severe spreading sepsis of the hand. The palm is explored
surgically and the flexor digiti minimi brevis muscle is mobilised to facilitate drainage of the
infection. Which of the following structures is not closely related to this muscle?
A. The hook of hamate
B. Median nerve
C. Superficial palmar arterial arch
D. Digital nerves arising from the ulnar nerve
E. None of the above
The flexor digiti minimi brevis originates from the Hamate, on its undersurface lie the ulnar
contribution to the superficial palmar arterial arch and digital nerves derived from the ulnar
nerve. The median nerve overlies the flexor tendons.
Hand
Anatomy of the hand
Bones 8 Carpal bones 5 Metacarpals 14 phalanges
Intrinsic Muscles 7 Interossei - Supplied by ulnar nerve
3 palmar-adduct fingers 4 dorsal- abduct fingers
Intrinsic muscles Lumbricals
Flex MCPJ and extend the IPJ. Origin deep flexor tendon and insertion dorsal extensor hood
mechanism. Innervation: 1st and 2nd- median nerve, 3rd and 4th- deep
branch of the ulnar nerve.
Thenar eminence Abductor pollicis brevis Opponens pollicis Flexor pollicis brevis
Hypothenar
eminence
Opponens digiti minimi Flexor digiti minimi brevis Abductor digiti minimi
Image sourced from Wikipedia
A 22 year old man develops an infection in the pulp of his little finger. What is the most
proximal site to which this infection may migrate?
A. The metacarpophalangeal joint
B. The distal interphalangeal joint
C. The proximal interphalangeal joint
D. Proximal to the flexor retinaculum
E. Immediately distal to the carpal tunnel
The 5th tendon sheath extends from the little finger to the proximal aspect of the carpal
tunnel. This carries a significant risk of allowing infections to migrate proximally.
Hand
Anatomy of the hand
Bones 8 Carpal bones 5 Metacarpals 14 phalanges
Intrinsic Muscles 7 Interossei - Supplied by ulnar nerve
3 palmar-adduct fingers 4 dorsal- abduct fingers
Intrinsic muscles Lumbricals
Flex MCPJ and extend the IPJ. Origin deep flexor tendon and insertion dorsal extensor hood
mechanism. Innervation: 1st and 2nd- median nerve, 3rd and 4th- deep
branch of the ulnar nerve.
Thenar eminence Abductor pollicis brevis Opponens pollicis Flexor pollicis brevis
Hypothenar
eminence
Opponens digiti minimi Flexor digiti minimi brevis Abductor digiti minimi
Image sourced from Wikipedia
Which of the following muscles is not innervated by the deep branch of the ulnar
nerve?
A. Adductor pollicis
B. Hypothenar muscles
C. All the interosseous muscles
D. Opponens pollicis
E. Third and fourth lumbricals
Ulnar nerve
Origin
C8, T1
Supplies (no muscles in the upper arm)
Flexor carpi ulnaris
Flexor digitorum profundus
Flexor digiti minimi
Abductor digiti minimi
Opponens digiti minimi
Adductor pollicis
Interossei muscle
Third and fourth lumbricals
Palmaris brevis
Path
Posteromedial aspect of ulna to flexor compartment of forearm, then along the
ulnar. Passes beneath the flexor carpi ulnaris muscle, then superficially
through the flexor retinaculum into the palm of the hand.
Branches
Branch Supplies
Articular branch Flexor carpi ulnaris
Medial half of the flexor digitorum profundus
Palmar cutaneous branch (Arises near Skin on the medial part of the palm
the middle of the forearm)
Dorsal cutaneous branch Dorsal surface of the medial part of the hand
Superficial branch Cutaneous fibres to the anterior surfaces of
the medial one and one-half digits
Deep branch Hypothenar muscles
All the interosseous muscles
Third and fourth lumbricals
Adductor pollicis
Medial head of the flexor pollicis brevis
Effects of injury
Damage at the
wrist
Wasting and paralysis of intrinsic hand muscles (claw
hand)
Wasting and paralysis of hypothenar muscles
Loss of sensation medial 1 and half fingers
Damage at the
elbow
Radial deviation of the wrist
Clawing less in 3rd and 4th digits
Which of the following structures lie between the lateral and medial heads of the
triceps muscle?
A. Radial nerve
B. Median nerve
C. Ulnar nerve
D. Axillary nerve
E. Medial cutaneous nerve of the forearm
The radial nerve runs in its groove on between the two heads. The ulnar nerve lies
anterior to the medial head. The axillary nerve passes through the quadrangular space.
This lies superior to lateral head of the triceps muscle and thus the lateral border of
the quadrangular space is the humerus. Therefore the correct answer is the radial
nerve.
Triceps
Origin Long head- infraglenoid tubercle of the scapula.
Lateral head- dorsal surface of the humerus, lateral and proximal
to the groove of the radial nerve
Medial head- posterior surface of the humerus on the
inferomedial side of the radial groove and both of the
intermuscular septae
Insertion Olecranon process of the ulna. Here the olecranon bursa is
between the triceps tendon and olecranon.
Some fibres insert to the deep fascia of the forearm, posterior
capsule of the elbow (preventing the capsule from being trapped
between olecranon and olecranon fossa during extension)
Innervation Radial nerve
Blood
supply
Profunda brachii artery
Action Elbow extension. The long head can adduct the humerus and and extend
it from a flexed position
Relations The radial nerve and profunda brachii vessels lie between the lateral and
medial heads
Into which of the following structures does the superior part of the fibrous capsule of
the shoulder joint insert?
A. The surgical neck of the humerus
B. The body of the humerus
C. The bicipital groove
D. Immediately distal to the greater tuberosity
E. The anatomical neck of the humerus
The shoulder joint is a shallow joint, hence its great mobility. However, this comes at
the expense of stability. The fibrous capsule attaches to the anatomical neck
superiorly and the surgical neck inferiorly
Shoulder joint
Shallow synovial ball and socket type of joint.
It is an inherently unstable joint, but is capable to a wide range of movement.
Stability is provided by muscles of the rotator cuff that pass from the scapula
to insert in the greater tuberosity (all except sub scapularis-lesser tuberosity).
Glenoid labrum
Fibrocartilaginous rim attached to the free edge of the glenoid cavity
Tendon of the long head of biceps arises from within the joint from the
supraglenoid tubercle, and is fused at this point to the labrum.
The long head of triceps attaches to the infraglenoid tubercle
Fibrous capsule
Attaches to the scapula external to the glenoid labrum and to the labrum itself
(postero-superiorly)
Attaches to the humerus at the level of the anatomical neck superiorly and the
surgical neck inferiorly
Anteriorly the capsule is in contact with the tendon of subscapularis,
superiorly with the supraspinatus tendon, and posteriorly with the tendons of
infraspinatus and teres minor. All these blend with the capsule towards their
insertion.
Two defects in the fibrous capsule; superiorly for the tendon of biceps.
Anteriorly there is a defect beneath the subscapularis tendon.
The inferior extension of the capsule is closely related to the axillary nerve at
the surgical neck and this nerve is at risk in anteroinferior dislocations. It also
means that proximally sited osteomyelitis may progress to septic arthritis.
Movements and muscles
Flexion Anterior part of deltoid
Pectoralis major
Biceps
Coracobrachialis
Extension Posterior deltoid
Teres major
Latissimus dorsi
Adduction Pectoralis major
Latissimus dorsi
Teres major
Coracobrachialis
Abduction Mid deltoid
Supraspinatus
Medial rotation Subscapularis
Anterior deltoid
Teres major
Latissimus dorsi
Lateral rotation Posterior deltoid
Infraspinatus
Teres minor
Important anatomical relations
Anteriorly Brachial plexus
Axillary artery and vein
Posterior Suprascapular nerve
Suprascapular vessels
Inferior Axillary nerve
Circumflex humeral vessels
سؤال غلط
Damage to the posterior cord of the brachial plexus will not result in any of the following
except:
A. Klumpkes palsy
B. Anaesthesia overlying the lateral aspect of the forearm
C. A warm sweaty hand on the affected side
D. Loss of flexion of the arm
E. Anaesthesia overlying the posterior surface of the arm
The radial nerve gives cutaneous branches which supply the forearm posteriorly and the arm
laterally. Division of the posterior cord will impair the upper level of cutaneous sensation.
However, the lateral cutaneous nerve of the forearm arises from the musculocutaneous
nerve and would be unaffected. Loss of sympathetic function would not result in a sweaty
hand. Klumpkes palsy occurs when the lower roots are C8-T1 are damaged.
Brachial plexus
Origin Anterior rami of C5 to T1
Sections of the
plexus
Roots, trunks, divisions, cords, branches Mnemonic:Real Teenagers Drink Cold Beer
Roots Located in the posterior triangle Pass between scalenus anterior and medius
Trunks Located posterior to middle third of clavicle Upper and middle trunks related superiorly to the subclavian
artery Lower trunk passes over 1st rib posterior to the subclavian
artery
Divisions Apex of axilla
Cords Related to axillary artery
Diagram illustrating the branches of the brachial plexus
Image sourced from Wikipedia
Cutaneous sensation of the upper limb
Image sourced from Wikipedia
A woman develops winging of the scapula following a Patey mastectomy. What is the
most likely cause?
A. Division of pectoralis minor to access level 3 axillary nodes
B. Damage to the brachial plexus during axillary dissection
C. Damage to the long thoracic nerve during axillary dissection
D. Division of the thoracodorsal trunk during axillary dissection
E. Damage to the thoracodorsal trunk during axillary dissection
Theme from January 2012 exam
The serratus anterior muscle is supplied by the long thoracic nerve which runs along
the surface of serratus anterior and is liable to injury during nodal dissection.
Although pectoralis minor is divided during a Patey mastectomy (now seldom
performed) it is rare for this alone to produce winging of the scapula.
Long thoracic nerve
Derived from ventral rami of C5, C6, and C7 (close to their emergence from
intervertebral foramina)
It runs downward and passes either anterior or posterior to the middle scalene
muscle
It reaches upper tip of serratus anterior muscle and descends on outer surface
of this muscle, giving branches into it
Winging of Scapula occurs in long thoracic nerve injury (most common) or
from spinal accessory nerve injury (which denervates the trapezius) or a dorsal
scapular nerve injury
Which of the following is not closely related to the capitate bone?
A. Lunate bone
B. Scaphoid bone
C. Ulnar nerve
D. Hamate bone
E. Trapezoid bone
The ulnar nerve and artery lie adjacent to the pisiform bone. The capitate bone
articulates with the lunate, scaphoid, hamate and trapezoid bones, which are
therefore closely related to it.
Capitate bone
This is the largest of the carpal bones. It is centrally placed with a rounded
head set into the cavities of the lunate and scaphoid bones. Flatter articular
surfaces are present for the hamate medially and the trapezoid laterally.
Distally the bone articulates predominantly with the middle metacarpal.
An injury to the spinal accessory nerve will affect which of the following
movements?
A. Lateral rotation of the arm
B. Adduction of the arm at the glenohumeral joint
C. Protraction of the scapula
D. Upward rotation of the scapula
E. Depression of the scapula
The spinal accessory nerve innervates trapezius. The entire muscle will retract the
scapula. However, its upper and lower fibres act together to upwardly rotate it.
Shoulder joint
Shallow synovial ball and socket type of joint.
It is an inherently unstable joint, but is capable to a wide range of movement.
Stability is provided by muscles of the rotator cuff that pass from the scapula
to insert in the greater tuberosity (all except sub scapularis-lesser tuberosity).
Glenoid labrum
Fibrocartilaginous rim attached to the free edge of the glenoid cavity
Tendon of the long head of biceps arises from within the joint from the
supraglenoid tubercle, and is fused at this point to the labrum.
The long head of triceps attaches to the infraglenoid tubercle
Fibrous capsule
Attaches to the scapula external to the glenoid labrum and to the labrum itself
(postero-superiorly)
Attaches to the humerus at the level of the anatomical neck superiorly and the
surgical neck inferiorly
Anteriorly the capsule is in contact with the tendon of subscapularis,
superiorly with the supraspinatus tendon, and posteriorly with the tendons of
infraspinatus and teres minor. All these blend with the capsule towards their
insertion.
Two defects in the fibrous capsule; superiorly for the tendon of biceps.
Anteriorly there is a defect beneath the subscapularis tendon.
The inferior extension of the capsule is closely related to the axillary nerve at
the surgical neck and this nerve is at risk in anteroinferior dislocations. It also
means that proximally sited osteomyelitis may progress to septic arthritis.
Movements and muscles
Flexion Anterior part of deltoid
Pectoralis major
Biceps
Coracobrachialis
Extension Posterior deltoid
Teres major
Latissimus dorsi
Adduction Pectoralis major
Latissimus dorsi
Teres major
Coracobrachialis
Abduction Mid deltoid
Supraspinatus
Medial rotation Subscapularis
Anterior deltoid
Teres major
Latissimus dorsi
Lateral rotation Posterior deltoid
Infraspinatus
Teres minor
Important anatomical relations
Anteriorly Brachial plexus
Axillary artery and vein
Posterior Suprascapular nerve
Suprascapular vessels
Inferior Axillary nerve
Circumflex humeral vessels
A 23 year old man falls over whilst intoxicated and a shard of glass transects his median
nerve at the proximal border of the flexor retinaculum. His tendons escape injury. Which of
the following features will not be present?
A. Weakness of thumb abduction
B. Loss of sensation on the dorsal aspect of the thenar eminence
C. Loss of power of opponens pollicis
D. Adduction and lateral rotation of the thumb at rest
E. Loss of power of abductor pollicis brevis
The median nerve may be injured proximal to the flexor retinaculum. This will result in loss
of flexor pollicis brevis, opponens pollicis and the first and second lumbricals. When the
patient is asked to close the hand slowly there is a lag of the index and middle fingers
reflecting the impaired lumbrical muscle function. The sensory changes are minor and do
not extend to the dorsal aspect of the thenar eminence.
Abductor pollicis longus will contribute to thumb abduction (and is innervated by the
posterior interosseous nerve) and therefore abduction will be weaker than prior to the
injury.
Median nerve
The median nerve is formed by the union of a lateral and medial root respectively from the
lateral (C5,6,7) and medial (C8 and T1) cords of the brachial plexus; the medial root passes
anterior to the third part of the axillary artery. The nerve descends lateral to the brachial
artery, crosses to its medial side (usually passing anterior to the artery). It passes deep to the
bicipital aponeurosis and the median cubital vein at the elbow.
It passes between the two heads of the pronator teres muscle, and runs on the deep surface
of flexor digitorum superficialis (within its fascial sheath).
Near the wrist it becomes superficial between the tendons of flexor digitorum superficialis
and flexor carpi radialis, deep to palmaris longus tendon. It passes deep to the flexor
retinaculum to enter the palm, but lies anterior to the long flexor tendons within the carpal
tunnel.
Branches
Region Branch
Upper arm No branches, although the nerve commonly communicates with the
musculocutaneous nerve
Forearm Pronator teres
Flexor carpi radialis
Palmaris longus
Flexor digitorum superficialis
Flexor pollicis longus
Flexor digitorum profundus (only the radial half)
Distal
forearm
Palmar cutaneous branch
Hand
(Motor)
Motor supply (LOAF)
Lateral 2 lumbricals Opponens pollicis Abductor pollicis brevis Flexor pollicis brevis
Hand
(Sensory)
Over thumb and lateral 2 ½ fingers On the palmar aspect this projects proximally, on the dorsal aspect only
the distal regions are innervated with the radial nerve providing the more proximal cutaneous innervation.
Patterns of damage
Damage at wrist
e.g. carpal tunnel syndrome paralysis and wasting of thenar eminence muscles and opponens pollicis (ape hand
deformity) sensory loss to palmar aspect of lateral (radial) 2 ½ fingers
Damage at elbow, as above plus:
unable to pronate forearm weak wrist flexion ulnar deviation of wrist
Anterior interosseous nerve (branch of median nerve)
leaves just below the elbow results in loss of pronation of forearm and weakness of long flexors of thumb and
index finger
Topography of the median nerve
Image sourced from Wikipedia
A 23 year old man falls and injures his hand. There are concerns that he may have a scaphoid
fracture as there is tenderness in his anatomical snuffbox on clinical examination. Which of
the following forms the posterior border of this structure?
A. Basilic vein
B. Radial artery
C. Extensor pollicis brevis
D. Abductor pollicis longus
E. Extensor pollicis longus
Theme from 2009 Exam
Theme from September 2012 Exam
Its boundaries are extensor pollicis longus, medially (posterior border) and laterally (anterior
border) by the tendons of abductor pollicis longus and extensor pollicis brevis.
Anatomical snuffbox
Posterior border Tendon of extensor pollicis longus
Anterior border Tendons of extensor pollicis brevis and abductor pollicis longus
Proximal border Styloid process of the radius
Distal border Apex of snuffbox triangle
Floor Trapezium and scaphoid
Content Radial artery
Image showing the anatomical snuffbox
Image sourced from Wikipedia
A 28 year old man is stabbed outside a nightclub in the upper arm. The median nerve is
transected. Which of the following muscles will demonstrate impaired function as a result?
A. Palmaris brevis
B. Second and third interossei
C. Adductor pollicis
D. Abductor pollicis longus
E. Abductor pollicis brevis
Palmaris brevis - Ulnar nerve
Palmar interossei- Ulnar nerve
Adductor pollicis - Ulnar nerve
Abductor pollicis longus - Posterior
interosseous nerve
Abductor pollicis brevis - Median
nerve
The median nerve innervates all the short muscles of the thumb except the adductor and
the deep head of the short flexor. Palmaris and the interossei are innervated by the ulnar
nerve.
Median nerve
The median nerve is formed by the union of a lateral and medial root respectively from the
lateral (C5,6,7) and medial (C8 and T1) cords of the brachial plexus; the medial root passes
anterior to the third part of the axillary artery. The nerve descends lateral to the brachial
artery, crosses to its medial side (usually passing anterior to the artery). It passes deep to the
bicipital aponeurosis and the median cubital vein at the elbow.
It passes between the two heads of the pronator teres muscle, and runs on the deep surface
of flexor digitorum superficialis (within its fascial sheath).
Near the wrist it becomes superficial between the tendons of flexor digitorum superficialis
and flexor carpi radialis, deep to palmaris longus tendon. It passes deep to the flexor
retinaculum to enter the palm, but lies anterior to the long flexor tendons within the carpal
tunnel.
Branches
Region Branch
Upper arm No branches, although the nerve commonly communicates with the
musculocutaneous nerve
Forearm Pronator teres
Flexor carpi radialis
Palmaris longus
Flexor digitorum superficialis
Flexor pollicis longus
Flexor digitorum profundus (only the radial half)
Distal
forearm
Palmar cutaneous branch
Hand
(Motor)
Motor supply (LOAF)
Lateral 2 lumbricals Opponens pollicis Abductor pollicis brevis Flexor pollicis brevis
Hand
(Sensory)
Over thumb and lateral 2 ½ fingers On the palmar aspect this projects proximally, on the dorsal aspect only
the distal regions are innervated with the radial nerve providing the more proximal cutaneous innervation.
Patterns of damage
Damage at wrist
e.g. carpal tunnel syndrome paralysis and wasting of thenar eminence muscles and opponens pollicis (ape hand
deformity) sensory loss to palmar aspect of lateral (radial) 2 ½ fingers
Damage at elbow, as above plus:
unable to pronate forearm weak wrist flexion ulnar deviation of wrist
Anterior interosseous nerve (branch of median nerve)
leaves just below the elbow results in loss of pronation of forearm and weakness of long flexors of thumb and
index finger
Topography of the median nerve
Image sourced from Wikipedia
Which of the following is not a branch of the posterior cord of the brachial plexus?
A. Thoracodorsal nerve
B. Axillary nerve
C. Radial nerve
D. Lower subscapular nerve
E. Musculocutaneous nerve
Mnemonic branches off the
posterior cord
S ubscapular (upper and
lower)
T horacodorsal
A xillary
R adial
The musculocutaneous nerve is a branch off the lateral cord.
Brachial plexus
Origin Anterior rami of C5 to T1
Sections of the
plexus
Roots, trunks, divisions, cords, branches Mnemonic:Real Teenagers Drink Cold Beer
Roots Located in the posterior triangle Pass between scalenus anterior and medius
Trunks Located posterior to middle third of clavicle Upper and middle trunks related superiorly to the subclavian
artery Lower trunk passes over 1st rib posterior to the subclavian
artery
Divisions Apex of axilla
Cords Related to axillary artery
Diagram illustrating the branches of the brachial plexus
Image sourced from Wikipedia
Cutaneous sensation of the upper limb
Image sourced from Wikipedia
A 56 year old machinist has his arm entrapped in a steel grinder and is brought to the
emergency department. On examination, he is unable to extend his
metacarpophalangeal joints and abduct his shoulder. He has weakness of his elbow
and wrist. What has been injured?
A. Ulnar nerve
B. Axillary nerve
C. Medial cord of brachial plexus
D. Lateral cord of brachial plexus
E. Posterior cord of brachial plexus
The posterior cord gives rise to:
Radial nerve ((innervates the triceps, brachioradialis, wrist extensors, and
finger extensors)
Axillary nerve (innervates deltoid and teres minor)
Upper subscapular nerve (innervates subscapularis)
Lower subscapular nerve (innervates teres major and subscapularis)
Thoracodorsal nerve (innervates latissimus dorsi)
Theme from September 2012 exam
This is a description of a posterior cord lesion. Remember that the posterior cord
gives rise to the axillary and radial nerve.
Cords of the brachial plexus
The brachial plexus cords are described according to their relationship with the
axillary artery. The cords pass over the 1st rib near to the dome of the lung and pass
beneath the clavicle immediately posterior to the subclavian artery.
Lateral cord
Anterior divisions of the upper and middle trunks form the lateral cord
Origin of the lateral pectoral nerve (C5, C6, C7)
Medial cord
Anterior division of the lower trunk forms the medial cord
Origin of the medial pectoral nerve (C8, T1), the medial brachial cutaneous
nerve (T1), and the medial antebrachial cutaneous nerve (C8, T1)
Posterior cord
Formed by the posterior divisions of the 3 trunks (C5-T1)
Origin of the upper and lower subscapular nerves (C7, C8 and C5, C6,
respectively) and the thoracodorsal nerve to the latissimus dorsi (also known
as the middle subscapular nerve, C6, C7, C8), axillary and radial nerve
A motor cyclist is involved in a road traffic accident causing severe right shoulder injuries. He
is found to have an adducted, medially rotated shoulder. The elbow is fully extended and the
forearm pronated. Which is the most likely diagnosis?
A. C8, T1 root lesion
B. C5, C6 root lesion
C. Radial nerve lesion
D. Ulnar nerve lesion
E. Axillary nerve lesion
Erbs Palsy C5, C6 lesion
The features include:
Waiter's tip position Loss of shoulder abduction (deltoid and supraspinatus paralysis) Loss of external rotation of the shoulder (paralysis of infraspinatus and teres major) Loss of elbow flexion (paralysis of biceps, brachialis and brachioradialis) Loss of forearm supination (paralysis of Biceps)
The motorcyclist has had an Erb's palsy (C5, C6 root lesion). This is commonly known to be
associated with birth injury when a baby has a shoulder dystocia.
Brachial plexus
Origin Anterior rami of C5 to T1
Sections of the
plexus
Roots, trunks, divisions, cords, branches Mnemonic:Real Teenagers Drink Cold Beer
Roots Located in the posterior triangle Pass between scalenus anterior and medius
Trunks Located posterior to middle third of clavicle Upper and middle trunks related superiorly to the subclavian
artery Lower trunk passes over 1st rib posterior to the subclavian
artery
Divisions Apex of axilla
Cords Related to axillary artery
Diagram illustrating the branches of the brachial plexus
Image sourced from Wikipedia
Cutaneous sensation of the upper limb
Image sourced from Wikipedia
A 23 year old man has a cannula inserted into his cephalic vein. Through which
structure does the cephalic vein pass?
A. Interosseous membrane
B. Triceps
C. Pectoralis major
D. Clavipectoral fascia
E. Tendon of biceps
The cephalic vein is a favored vessel for arteriovenous fistula formation and should be
preserved in patients with end stage renal failure
The cephalic vein penetrates the calvipectoral fascia (but not the pectoralis major)
prior to terminating in the axillary vein.
Cephalic vein
Path
Dorsal venous arch drains laterally into the cephalic vein
Crosses the anatomical snuffbox and travels laterally up the arm
At the antecubital fossa connected to the basilic vein by the median cubital
vein
Pierces deep fascia of deltopectoral groove to join axillary vein
Rate questio
Which of the following is not a muscle of the rotator cuff?
A. Subscapularis
B. Teres minor
C. Supraspinatus
D. Infraspinatus
E. Deltoid
Deltoid may abduct the shoulder and is not a rotator cuff muscle.
Muscles of the rotator cuff
Muscle Innervation
Supraspinatus muscle Suprascapular nerve
Infraspinatus muscle Suprascapular nerve
Teres minor muscle Axillary nerve
Subscapularis muscle Superior and inferior subscapular nerves
A 32 year old man is stabbed in the neck and the inferior trunk of his brachial plexus is
injured. Which of the modalities listed below is least likely to be affected?
A. Initiating abduction of the shoulder
B. Abduction of the fingers
C. Flexion of the little finger
D. Sensation on the palmar aspect of the little finger
E. Gripping a screwdriver
Inferior trunk of brachial plexus.
C8 and T1 roots Contributes to ulnar nerve and
part of median nerve
Theme from September 2012 Exam
The inferior trunk of the brachial plexus is rarely injured. Nerve roots C8 and T1 are the main
contributors to this trunk. Therefore an injury to this site will most consistently affect the
ulnar nerve. The inferior trunk also contributes to the median nerve by way of the posterior
division and therefore some impairment of grip is almost inevitable.
Brachial plexus
Origin Anterior rami of C5 to T1
Sections of the
plexus
Roots, trunks, divisions, cords, branches Mnemonic:Real Teenagers Drink Cold Beer
Roots Located in the posterior triangle Pass between scalenus anterior and medius
Trunks Located posterior to middle third of clavicle Upper and middle trunks related superiorly to the subclavian
artery Lower trunk passes over 1st rib posterior to the subclavian
artery
Divisions Apex of axilla
Cords Related to axillary artery
Diagram illustrating the branches of the brachial plexus
Image sourced from Wikipedia
Cutaneous sensation of the upper limb
Image sourced from Wikipedia
As it exits the axilla the radial nerve lies on which of the following muscles?
A. Supraspinatus
B. Infraspinatus
C. Teres major
D. Deltoid
E. Pectoralis major
The radial nerve passes through the triangular space to leave the axilla. The superior border
of this is bounded by the teres major muscle to which the radial nerve is closely related.
Radial nerve
Continuation of posterior cord of the brachial plexus (root values C5 to T1)
Path
In the axilla: lies posterior to the axillary artery on subscapularis, latissimus dorsi and teres major.
Enters the arm between the brachial artery and the long head of triceps (medial to humerus).
Spirals around the posterior surface of the humerus in the groove for the radial nerve.
At the distal third of the lateral border of the humerus it then pierces the intermuscular septum and descends in front of the lateral epicondyle.
At the lateral epicondyle it lies deeply between brachialis and brachioradialis where it then divides into a superficial and deep terminal branch.
Deep branch crosses the supinator to become the posterior interosseous nerve.
In the image below the relationships of the radial nerve can be appreciated
Image sourced from Wikipedia
Regions innervated
Motor (main nerve) Triceps Anconeus Brachioradialis Extensor carpi radialis
Motor (posterior
interosseous
branch
Extensor carpi ulnaris Extensor digitorum Extensor indicis Extensor digiti minimi Extensor pollicis longus and brevis Abductor pollicis longus
Sensory The area of skin supplying the proximal phalanges on the dorsal aspect
of the hand is supplied by the radial nerve (this does not apply to the
little finger and part of the ring finger)
Muscular innervation and effect of denervation
Anatomical
location
Muscle affected Effect of paralysis
Shoulder Long head of triceps Minor effects on shoulder stability in
abduction
Arm Triceps Loss of elbow extension
Forearm Supinator
Brachioradialis
Extensor carpi radialis
longus and brevis
Weakening of supination of prone hand and
elbow flexion in mid prone position
The cutaneous sensation of the upper limb- illustrating the contribution of the radial nerve
Image sourced from Wikipedia
A 62 year old man presents with arm weakness. On examination he has a weakness of elbow
extension and loss of sensation on the dorsal aspect of the first digit. What is the site of the
most likely underlying defect?
A. Axillary nerve
B. Median nerve
C. Ulnar nerve
D. Radial nerve
E. Musculocutaneous nerve
Theme from April 2012 Exam
The long head of the triceps muscle may be innervated by the axillary nerve and therefore
complete loss of triceps muscles function may not be present even with proximally sited
nerve lesions.
Radial nerve
Continuation of posterior cord of the brachial plexus (root values C5 to T1)
Path
In the axilla: lies posterior to the axillary artery on subscapularis, latissimus dorsi and teres major.
Enters the arm between the brachial artery and the long head of triceps (medial to humerus).
Spirals around the posterior surface of the humerus in the groove for the radial nerve.
At the distal third of the lateral border of the humerus it then pierces the intermuscular septum and descends in front of the lateral epicondyle.
At the lateral epicondyle it lies deeply between brachialis and brachioradialis where it then divides into a superficial and deep terminal branch.
Deep branch crosses the supinator to become the posterior interosseous nerve.
In the image below the relationships of the radial nerve can be appreciated
Image sourced from Wikipedia
Regions innervated
Motor (main nerve) Triceps Anconeus Brachioradialis Extensor carpi radialis
Motor (posterior
interosseous
branch
Extensor carpi ulnaris Extensor digitorum Extensor indicis Extensor digiti minimi Extensor pollicis longus and brevis Abductor pollicis longus
Sensory The area of skin supplying the proximal phalanges on the dorsal aspect
of the hand is supplied by the radial nerve (this does not apply to the
little finger and part of the ring finger)
Muscular innervation and effect of denervation
Anatomical
location
Muscle affected Effect of paralysis
Shoulder Long head of triceps Minor effects on shoulder stability in
abduction
Arm Triceps Loss of elbow extension
Forearm Supinator
Brachioradialis
Extensor carpi radialis
longus and brevis
Weakening of supination of prone hand and
elbow flexion in mid prone position
The cutaneous sensation of the upper limb- illustrating the contribution of the radial nerve
Im
From which of the following structures does the long head of the triceps muscle arise?
A. Coracoid process
B. Acromion
C. Infraglenoid tubercle
D. Coraco-acromial ligament
E. Coraco-humeral ligament
The long head arises from the infraglenoid tubercle. The fleshy lateral and medial
heads are attached to the posterior aspect of the humerus between the insertion of the
teres minor and the olecranon fossa.
Triceps
Origin Long head- infraglenoid tubercle of the scapula.
Lateral head- dorsal surface of the humerus, lateral and proximal
to the groove of the radial nerve
Medial head- posterior surface of the humerus on the
inferomedial side of the radial groove and both of the
intermuscular septae
Insertion Olecranon process of the ulna. Here the olecranon bursa is
between the triceps tendon and olecranon.
Some fibres insert to the deep fascia of the forearm, posterior
capsule of the elbow (preventing the capsule from being trapped
between olecranon and olecranon fossa during extension)
Innervation Radial nerve
Blood
supply
Profunda brachii artery
Action Elbow extension. The long head can adduct the humerus and and extend
it from a flexed position
Relations The radial nerve and profunda brachii vessels lie between the lateral and
medial heads
A 58 year old lady presents with a mass in the upper outer quadrant of the right breast.
Which of the following statements relating to the breast is untrue?
A. The internal mammary artery provides the majority of its arterial supply
B. Nipple retraction may occur as a result of tumour infiltration of the
clavipectoral fascia
C. The internal mammary artery is a branch of the subclavian artery
D. Up to 70% of lymphatic drainage is to the ipsilateral axillary nodes
E. None of the above
Nipple retraction is a feature of breast malignancy. However, it is typically caused by tumour
infiltration of Coopers Ligaments that run through the breast and surround the lobules. The
clavipectoral fascia encases the axillary contents. The lymphatic drainage of the breast is to
the axilla and also to the internal mammary chain. The breast is well vascularised and the
internal mammary artery is a branch of the subclavian artery.
Breast
The breast itself lies on a layer of pectoral fascia and the following muscles:
1. Pectoralis major
2. Serratus anterior
3. External oblique
Image showing the topography of the female breast
Image sourced from Wikipedia
Breast anatomy
Nerve supply Branches of intercostal nerves from T4-T6.
Arterial supply Internal mammary (thoracic) artery External mammary artery (laterally) Anterior intercostal arteries Thoraco-acromial artery
Venous drainage Superficial venous plexus to sub clavian, axillary and intercostal veins.
Lymphatic
drainage
70% Axillary nodes Internal mammary chain Other lymphatic sites such as deep cervical and supraclavicular
fossa (later in disease)
Theme: Nerve injury
A. Median nerve
B. Ulnar nerve
C. Radial nerve
D. Anterior interosseous nerve
E. Posterior interosseous nerve
F. Axillary nerve
G. Musculocutaneous nerve
Please select the nerve at risk of injury in each scenario. Each option may be used once,
more than once or not at all.
290. A 43 year old typist presents with pain at the dorsal aspect of the upper part of her
forearm. She also complains of weakness when extending her fingers. On
examination triceps and supinator are both functioning normally. There is weakness
of most of the extensor muscles. However, there is no sensory deficit.
Posterior interosseous nerve
The radial nerve may become entrapped in the "arcade of Frohse" which is a
superficial part of the supinator muscle which overlies the posterior interosseous
nerve. This nerve is entirely muscular and articular in its distribution. It passes
postero-inferiorly and gives branches to extensor carpi radialis brevis and
supinator. It enters supinator and curves around the lateral and posterior surfaces
of the radius. On emerging from the supinator the posterior interosseous nerve lies
between the superficial extensor muscles and the lowermost fibres of supinator. It
then gives branches to the extensors.
291. A 28 year teacher reports difficulty with writing. There is no sensory loss. She is
known to have an aberrant Gantzer muscle.
You answered Posterior interosseous nerve
The correct answer is Anterior interosseous nerve
Anterior interosseous lesions occur due to fracture, or rarely due to compression.
The Gantzer muscle is an aberrant accessory of the flexor pollicis longus and is a risk
factor for anterior interosseous nerve compression. Remember loss of pincer grip
and normal sensation indicates an interosseous nerve lesion.
292. A 35 year tennis player attends reporting tingling down his arm. He says that his
'funny bone' was hit very hard by a tennis ball. There is weakness of abduction and
adduction of his extended fingers.
Ulnar nerve
Theme from September 2012 exam
The ulnar nerve arises from the medial cord of the brachial plexus (C8, T1 and
contribution from C7). The nerve descends between the axillary artery and vein,
posterior to the cutaneous nerve of the forearm and then lies anterior to triceps on
the medial side of the brachial artery. In the distal half of the arm it passes through
the medial intermuscular septum, and continues between this structure and the
medial head of triceps to enter the forearm between the medial epicondyle of the
humerus and the olecranon. It may be injured at this site in this scenario.
Brachial plexus
Origin Anterior rami of C5 to T1
Sections of the
plexus
Roots, trunks, divisions, cords, branches Mnemonic:Real Teenagers Drink Cold Beer
Roots Located in the posterior triangle Pass between scalenus anterior and medius
Trunks Located posterior to middle third of clavicle Upper and middle trunks related superiorly to the subclavian
artery Lower trunk passes over 1st rib posterior to the subclavian
artery
Divisions Apex of axilla
Cords Related to axillary artery
Diagram illustrating the branches of the brachial plexus
Image sourced from Wikipedia
Cutaneous sensation of the upper limb
Image sourced from Wikipedia
A 53 year old lady presents with pain and discomfort in her hand. She works as a typist and
notices that the pain is worst when she is working. She also suffers symptoms at night. Her
little finger is less affected by the pain. Which of the nerves listed below is most likely to be
affected?
A. Radial
B. Median
C. Ulnar
D. Anterior interosseous nerve
E. Posterior interosseous nerve
Motor supply: LOAF
L ateral 2 lumbricals
O pponens pollicis
A bductor
pollicisbrevis
F lexor pollicis
brevis
Theme from April 2012 Exam
The most likely diagnosis here is carpal tunnel syndrome, the median nerve is compressed in
the wrist and symptoms usually affect the fingers and wrist either at night or when the hand
is being used (e.g. as a typist).
Median nerve
The median nerve is formed by the union of a lateral and medial root respectively from the
lateral (C5,6,7) and medial (C8 and T1) cords of the brachial plexus; the medial root passes
anterior to the third part of the axillary artery. The nerve descends lateral to the brachial
artery, crosses to its medial side (usually passing anterior to the artery). It passes deep to the
bicipital aponeurosis and the median cubital vein at the elbow.
It passes between the two heads of the pronator teres muscle, and runs on the deep surface
of flexor digitorum superficialis (within its fascial sheath).
Near the wrist it becomes superficial between the tendons of flexor digitorum superficialis
and flexor carpi radialis, deep to palmaris longus tendon. It passes deep to the flexor
retinaculum to enter the palm, but lies anterior to the long flexor tendons within the carpal
tunnel.
Branches
Region Branch
Upper arm No branches, although the nerve commonly communicates with the
musculocutaneous nerve
Forearm Pronator teres
Flexor carpi radialis
Palmaris longus
Flexor digitorum superficialis
Flexor pollicis longus
Flexor digitorum profundus (only the radial half)
Distal
forearm
Palmar cutaneous branch
Hand
(Motor)
Motor supply (LOAF)
Lateral 2 lumbricals Opponens pollicis
Abductor pollicis brevis Flexor pollicis brevis
Hand
(Sensory)
Over thumb and lateral 2 ½ fingers On the palmar aspect this projects proximally, on the dorsal aspect only
the distal regions are innervated with the radial nerve providing the more proximal cutaneous innervation.
Patterns of damage
Damage at wrist
e.g. carpal tunnel syndrome paralysis and wasting of thenar eminence muscles and opponens pollicis (ape hand
deformity) sensory loss to palmar aspect of lateral (radial) 2 ½ fingers
Damage at elbow, as above plus:
unable to pronate forearm weak wrist flexion ulnar deviation of wrist
Anterior interosseous nerve (branch of median nerve)
leaves just below the elbow results in loss of pronation of forearm and weakness of long flexors of thumb and
index finger
Topography of the median nerve
Image sourced from Wikipedia
A 24 year female is admitted to A&E with tingling of her hand after a fall. She is found to
have a fracture of the medial epicondyle. What is the most likely nerve lesion?
A. Ulnar nerve
B. Radial nerve
C. Median nerve
D. Axillary nerve
E. Cutaneous nerve
The radial nerve is located near the lateral epicondyle.
Ulnar nerve
Origin
C8, T1
Supplies (no muscles in the upper arm)
Flexor carpi ulnaris Flexor digitorum profundus Flexor digiti minimi Abductor digiti minimi Opponens digiti minimi Adductor pollicis Interossei muscle Third and fourth lumbricals Palmaris brevis
Path
Posteromedial aspect of ulna to flexor compartment of forearm, then along the ulnar. Passes beneath the flexor carpi ulnaris muscle, then superficially through the flexor retinaculum into the palm of the hand.
Image sourced from Wikipedia
Branches
Branch Supplies
Articular branch Flexor carpi ulnaris
Medial half of the flexor digitorum profundus
Palmar cutaneous branch (Arises near the
middle of the forearm)
Skin on the medial part of the palm
Dorsal cutaneous branch Dorsal surface of the medial part of the hand
Superficial branch Cutaneous fibres to the anterior surfaces of the
medial one and one-half digits
Deep branch Hypothenar muscles
All the interosseous muscles
Third and fourth lumbricals
Adductor pollicis
Medial head of the flexor pollicis brevis
Effects of injury
Damage at the wrist Wasting and paralysis of intrinsic hand muscles (claw hand) Wasting and paralysis of hypothenar muscles Loss of sensation medial 1 and half fingers
Damage at the
elbow
Radial deviation of the wrist Clawing less in 3rd and 4th digits
A 43 year old lady is undergoing an axillary node clearance for breast cancer. The
nodal disease is bulky. During clearance of the level 3 nodes there is suddenly brisk
haemorrhage. The most likely vessel responsible is:
A. Thoracoacromial artery
B. Cephalic vein
C. Thoracodorsal trunk
D. Internal mammary artery
E. Posterior circumflex humeral artery
The thoracoacromial artery pierces the pectoralis major and gives off branches within
this space. The level 3 axillary nodes lie between pectoralis major and
minor.Although the thoracodorsal trunk may be injured during an axillary dissection it
does not lie within the level 3 nodes.
Thoracoacromial artery
The thoracoacromial artery (acromiothoracic artery; thoracic axis) is a short trunk,
which arises from the forepart of the axillary artery, its origin being generally
overlapped by the upper edge of the Pectoralis minor.
Projecting forward to the upper border of the Pectoralis minor, it pierces the
coracoclavicular fascia and divides into four branches: pectoral, acromial, clavicular,
and deltoid.
Branch Description
Pectoral
branch
Descends between the two Pectoral muscles, and is distributed to them
and to the breast, anastomosing with the intercostal branches of the
internal thoracic artery and with the lateral thoracic.
Acromial
branch
Runs laterally over the coracoid process and under the Deltoid, to which
it gives branches; it then pierces that muscle and ends on the acromion in
an arterial network formed by branches from the suprascapular,
thoracoacromial, and posterior humeral circumflex arteries.
Clavicular
branch
Runs upwards and medially to the sternoclavicular joint, supplying this
articulation, and the Subclavius
Deltoid
branch
Arising with the acromial, it crosses over the Pectoralis minor and passes
in the same groove as the cephalic vein, between the Pectoralis major and
Deltoid, and gives branches to both muscles.
A 73 year old lady with long standing atrial fibrillation develops a cold and pulseless
white arm. A brachial embolus is suspected and a brachial embolectomy is performed.
Which of the following structures is at greatest risk of injury during this procedure?
A. Radial nerve
B. Cephalic vein
C. Ulnar nerve
D. Median nerve
E. None of the above
The median nerve lies close to the brachial artery in the antecubital fossa. This is the
usual site of surgical access to the brachial artery for an embolectomy procedure. The
median nerve may be damaged during clumsy application of vascular clamps to the
artery.
Brachial artery
The brachial artery begins at the lower border of teres major as a continuation of the
axillary artery. It terminates in the cubital fossa at the level of the neck of the radius
by dividing into the radial and ulnar arteries.
Relations Posterior relations include the long head of triceps with the radial nerve and profunda
vessels intervening. Anteriorly it is overlapped by the medial border of biceps.
It is crossed by the median nerve in the middle of the arm.
In the cubital fossa it is separated from the median cubital vein by the bicipital
aponeurosis.
The basilic vein is in contact at the most proximal aspect of the cubital fossa and lies
medially. Which of the following fingers is not a point of attachment for the palmar interossei?
A. Middle finger
B. Little finger
C. Ring finger
D. Index finger
E. None of the above
The middle finger has no attachment of the palmar interosseous.
Image sourced from Wikipedia
Hand
Anatomy of the hand
Bones 8 Carpal bones 5 Metacarpals 14 phalanges
Intrinsic Muscles 7 Interossei - Supplied by ulnar nerve
3 palmar-adduct fingers 4 dorsal- abduct fingers
Intrinsic muscles Lumbricals
Flex MCPJ and extend the IPJ. Origin deep flexor tendon and insertion dorsal extensor hood
mechanism. Innervation: 1st and 2nd- median nerve, 3rd and 4th- deep
branch of the ulnar nerve.
Thenar eminence Abductor pollicis brevis Opponens pollicis Flexor pollicis brevis
Hypothenar
eminence
Opponens digiti minimi Flexor digiti minimi brevis Abductor digiti minimi
Image sourced from Wikipedia
A 6 year old sustains a supracondylar fracture of the distal humerus. There are concerns that
the radial nerve may have been injured. What is the relationship of the radial nerve to the
humerus at this point?
A. Anterolateral
B. Anteromedial
C. Posterolateral
D. Posteromedial
E. Immediately anterior
The radial nerve lies anterolateral to the humerus in the supracondylar area.
Radial nerve
Continuation of posterior cord of the brachial plexus (root values C5 to T1)
Path
In the axilla: lies posterior to the axillary artery on subscapularis, latissimus dorsi and teres major.
Enters the arm between the brachial artery and the long head of triceps (medial to humerus).
Spirals around the posterior surface of the humerus in the groove for the radial nerve.
At the distal third of the lateral border of the humerus it then pierces the intermuscular septum and descends in front of the lateral epicondyle.
At the lateral epicondyle it lies deeply between brachialis and brachioradialis where it then divides into a superficial and deep terminal branch.
Deep branch crosses the supinator to become the posterior interosseous nerve.
In the image below the relationships of the radial nerve can be appreciated
Image sourced from Wikipedia
Regions innervated
Motor (main nerve) Triceps Anconeus Brachioradialis Extensor carpi radialis
Motor (posterior
interosseous
branch
Extensor carpi ulnaris Extensor digitorum Extensor indicis Extensor digiti minimi Extensor pollicis longus and brevis Abductor pollicis longus
Sensory The area of skin supplying the proximal phalanges on the dorsal aspect
of the hand is supplied by the radial nerve (this does not apply to the
little finger and part of the ring finger)
Muscular innervation and effect of denervation
Anatomical
location
Muscle affected Effect of paralysis
Shoulder Long head of triceps Minor effects on shoulder stability in
abduction
Arm Triceps Loss of elbow extension
Forearm Supinator
Brachioradialis
Extensor carpi radialis
longus and brevis
Weakening of supination of prone hand and
elbow flexion in mid prone position
The cutaneous sensation of the upper limb- illustrating the contribution of the radial nerve
Image sourced from Wikipedia
The following are true of the ulnar nerve except:
A. It innervates the palmar interossei
B. Derived from the medial cord of the brachial plexus
C. Supplies the muscles of the thenar eminence
D. Supplies the medial half of flexor digitorum profundus
E. Passes superficial to the flexor retinaculum
These are supplied by the median nerve and atrophy of these is a feature of carpal tunnel
syndrome
Ulnar nerve
Origin
C8, T1
Supplies (no muscles in the upper arm)
Flexor carpi ulnaris Flexor digitorum profundus Flexor digiti minimi Abductor digiti minimi Opponens digiti minimi Adductor pollicis Interossei muscle Third and fourth lumbricals Palmaris brevis
Path
Posteromedial aspect of ulna to flexor compartment of forearm, then along the ulnar. Passes beneath the flexor carpi ulnaris muscle, then superficially through the flexor retinaculum into the palm of the hand.
Image sourced from Wikipedia
Branches
Branch Supplies
Articular branch Flexor carpi ulnaris
Medial half of the flexor digitorum profundus
Palmar cutaneous branch (Arises near the
middle of the forearm)
Skin on the medial part of the palm
Dorsal cutaneous branch Dorsal surface of the medial part of the hand
Superficial branch Cutaneous fibres to the anterior surfaces of the
medial one and one-half digits
Deep branch Hypothenar muscles
All the interosseous muscles
Third and fourth lumbricals
Adductor pollicis
Medial head of the flexor pollicis brevis
Effects of injury
Damage at the wrist Wasting and paralysis of intrinsic hand muscles (claw hand) Wasting and paralysis of hypothenar muscles Loss of sensation medial 1 and half fingers
Damage at the
elbow
Radial deviation of the wrist Clawing less in 3rd and 4th digits
Which muscle is responsible for causing flexion of the distal interphalangeal joint of the ring
finger?
A. Flexor digitorum superficialis
B. Lumbricals
C. Palmar interossei
D. Flexor digitorum profundus
E. Flexor digiti minimi brevis
Flexor digitorum superficialis and flexor digitorum profundus are responsible for causing
flexion. The superficialis tendons insert on the bases of the middle phalanges; the profundus
tendons insert on the bases of the distal phalanges. Both tendons flex the wrist, MCP and
PIP joints; however, only the profundus tendons flex the DIP joints.
Hand
Anatomy of the hand
Bones 8 Carpal bones 5 Metacarpals 14 phalanges
Intrinsic Muscles 7 Interossei - Supplied by ulnar nerve
3 palmar-adduct fingers
4 dorsal- abduct fingers
Intrinsic muscles Lumbricals
Flex MCPJ and extend the IPJ. Origin deep flexor tendon and insertion dorsal extensor hood
mechanism. Innervation: 1st and 2nd- median nerve, 3rd and 4th- deep
branch of the ulnar nerve.
Thenar eminence Abductor pollicis brevis Opponens pollicis Flexor pollicis brevis
Hypothenar
eminence
Opponens digiti minimi Flexor digiti minimi brevis Abductor digiti minimi
Image sourced from Wikipedia
Which of the following muscles lies medial to the long thoracic nerve?
A. Serratus anterior
B. Latissimus dorsi
C. Pectoralis major
D. Pectoralis minor
E. None of the above
Theme from 2009 Exam
Long thoracic nerve
Derived from ventral rami of C5, C6, and C7 (close to their emergence from intervertebral
foramina)
It runs downward and passes either anterior or posterior to the middle scalene muscle
It reaches upper tip of serratus anterior muscle and descends on outer surface of this
muscle, giving branches into it
Winging of Scapula occurs in long thoracic nerve injury (most common) or from spinal
accessory nerve injury (which denervates the trapezius) or a dorsal scapular nerve injury