Anatomy of Forearm and Wrist

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ObjectivesObjectives

• Skeleton Skeleton • anatomical land marks,anatomical land marks,• cutaneous nerves, cutaneous nerves, • dermatomesdermatomes• superficial veins superficial veins • lymphatics lymphatics • compartments andcompartments and

the structures in the structures in themthem

• Space of Parona.Space of Parona.

• structures in the structures in the region of wrist region of wrist • carpal tunnel carpal tunnel •Eg.s of clinical aspects.Eg.s of clinical aspects.

Base - line joining the epicondyles Medial - pronator teres.MLateral – brachioradialis.MRoof -skin, -fascia and -bicipital aponeurosisFloor - capsule of elbow joint, brachialis.M supinator.M

Bounderies of cubital fossa:

Cubital fossa merges the arm to forearm.

Contents in the cubital fossa-- medial to Contents in the cubital fossa-- medial to laterallateral

• Median nerveMedian nerve• Brachial artery Brachial artery

(with terminal branches)(with terminal branches)• Biceps brachii tendonBiceps brachii tendon• Structures on the roof ;Structures on the roof ;• Basilic and cephalic veins Basilic and cephalic veins • Cutaneous nerves of forearmCutaneous nerves of forearm

(medial and lateral.) • Median cubital vein and its communications.

•Note; radial.N and terminal branches- deep to lateral boundery.

Skeleton- Radius ulna and interosseous Radius ulna and interosseous membranemembrane

Anatomical/surface land marks Anatomical/surface land marks – Medial and lateral epicondylesMedial and lateral epicondyles– OlecrenonOlecrenon– Head of radiusHead of radius– Subcutaneous border of ulnaSubcutaneous border of ulna– Lower ends of radius and ulnaLower ends of radius and ulna– Styloid processes of radius and ulnaStyloid processes of radius and ulna– Dorsal tubercle of radiusDorsal tubercle of radius– Visible and palpable tendons.Visible and palpable tendons.

Medial, lateral &Medial, lateral &

posterior cutaneous nerves of forearm.posterior cutaneous nerves of forearm.Anterior viewPosterior view

Cutaneous nerves Cutaneous nerves of forearm--of forearm--

Dermatomes of Dermatomes of forearmforearm

C5

Superficial Superficial veins veins

Cephalic veinCephalic vein

Basilic veinBasilic vein

Superficial forearm veinsSuperficial forearm veins

Median cubital.vMedian cubital.v

Median cephalic.vMedian cephalic.v

Median basilic.vMedian basilic.v

Peripheral intravenous Peripheral intravenous access.access.

From dorsal venous arch

Superficial lymphatics follow the superficial veins;

- medial side- go to supratrochlear / epitrochlear nodes and then to the lateral group of axillary nodes - Lateral side - go to infraclavicular nodes

Compartments of the forearm:Compartments of the forearm:

• Flexor (anterior) compartment,Flexor (anterior) compartment,

• Extensor (posterior) compartmentExtensor (posterior) compartment

Flexor compartment;

Superficial Muscles:1. Pronator teres, M.N

2. Flexor carpi radialis,M.N

3. Palmaris longus, M.N

4. Flexor digitorum- superficialis, M.N

5. Flexor carpi ulnaris. U.N

1 and 2 = C6 7

3, 4 and 6 = C7 8

Superficial muscles arises from -Superficial muscles arises from -

-Medial epicondyle of humerus=common flexor -Medial epicondyle of humerus=common flexor origin. origin.

In addition three of them have additional origin,In addition three of them have additional origin,

-Fl. Dig.Suprficialis --med.Lig of elbow, radius & -Fl. Dig.Suprficialis --med.Lig of elbow, radius & ulna. ulna.

-Pronator teres – humerus and ulna. – humerus and ulna.

-Fl. Car. Ulnaris -- ulna. -Fl. Car. Ulnaris -- ulna.

Superficial muscles - origin and Superficial muscles - origin and insertioninsertion

Deep musclesDeep muscles..

Flexor digitorum Flexor digitorum profundus- profundus-

Flexor pollicis Flexor pollicis longus,longus,

Pronator quadratus,Pronator quadratus,

Flexor compartment-

Flexor digitorum profundus- Flexor digitorum profundus- Flexor pollicis longus,Flexor pollicis longus,

Pronator quadratus,Pronator quadratus,

Origin and insertion of deep of deep muscles:muscles:

An

teri

or

asp

ect

Deep muscles ; nerve Deep muscles ; nerve supplysupply

1.1.Flexor digitorum profundus,Flexor digitorum profundus, medial part - ---- medial part - ---- Ulnar.N Ulnar.N lateral part– anterior lateral part– anterior interosseous .N interosseous .N

2. Flexor pollicis longus,2. Flexor pollicis longus, anterior interosseous.Nanterior interosseous.N

3. Pronator quadratus,3. Pronator quadratus, anterior interosseous.N.anterior interosseous.N.

1 = C7, 8 and T11 = C7, 8 and T12 = C8 and T12 = C8 and T1

Action of muscles of flexor compartment-Action of muscles of flexor compartment-

Superficial Muscles: Pronator teres, Flexor carpi radialis, Palmaris longus, Flexor digitorum- superficialis, Flexor carpi ulnaris,

NoteNote thumb has only one interphalangeal thumb has only one interphalangeal joint.joint.

Deep muscles

- Flexor digitorum - Flexor digitorum profundus,profundus,

- Flexor pollicis longus,- Flexor pollicis longus,

- Pronator quadratus,- Pronator quadratus,

On joints from elbow to distal inter-phalangeal On joints from elbow to distal inter-phalangeal joints.joints.

Nerves of flexor compartment of Nerves of flexor compartment of forearm.forearm.

Median nerve, Median nerve, C5,6,7,8,T1 C5,6,7,8,T1

Anterior Anterior interosseous .N.interosseous .N.= a branch of median = a branch of median nerve nerve

Ulnar nerve, C7,8,T1.

Course and relations in this compartment.

- - branches to branches to superficial muscles, superficial muscles,

- - aanterior interosseous branch to -deep muscles(except medial part of

flex.dig.pro) -inferior radio-ulnar joint - articular branches to elbow, sup. radioulnar and wrist joints, - palmar cutaneous branch.

Branches of Branches of median nervemedian nerve in the anterior compartment of forearm;

Branches of ulnar nerve in the forearm.

- muscular branches to to flexor carpi ulnaris, flexor digitorum profundus-medial part,

- articular branch to elbow and wrist joints,articular branch to elbow and wrist joints,

At the wrist givesAt the wrist gives- dorsal branch,dorsal branch,- Superficial and deep branches.Superficial and deep branches.

Blood vessels in the Blood vessels in the anterior anterior compartment compartment ..-Radial.A

-Ulnar.A-Anterior interosseus. A-Median artery (persistant part of axial artery of fetal limb).

Venae comitantes of radial and ulnar arteries join to form venae comitantes of brachial artery.DeepDeep lymphatics travel lymphatics travel along the deep blood vessel along the deep blood vessel and go to lateral group of and go to lateral group of axillary nodes.axillary nodes.

Anterior interosseous atrery suppliesanterior compartment .

Space of Parona Space of Parona superficial to the pronator quadratus,superficial to the pronator quadratus,deep to the long flexor tendons, deep to the long flexor tendons,

upper limit- oblique origin ofupper limit- oblique origin of flexor digitorum superficialis. flexor digitorum superficialis.

flexor tendon sheaths protrudeflexor tendon sheaths protrudeinto this spaceinto this space

flexor sheath infections canflexor sheath infections canextend into this space.extend into this space.

Muscles: Muscles: Extensor carpi radialis Extensor carpi radialis longus,longus,

Extensor carpi radialis brevis, Extensor carpi radialis brevis,

Extensor digitorum, Extensor digitorum,

Extensor digiti minimi, Extensor digiti minimi,

Extensor carpi ulnaris, Extensor carpi ulnaris, Anconeus.Anconeus.

Extensor (Posterior) compartment of forearm ::

Supinator,Supinator,

Abductor pollicis Abductor pollicis longus,longus,

Extensor pollicis Extensor pollicis longus,longus,

Extensor pollicis Extensor pollicis brevis,brevis,

Extensor indicis.Extensor indicis.

Superficial extensors arise Superficial extensors arise from; - from; - common extensor origin on common extensor origin on lateral epicondyle of the lateral epicondyle of the humarushumarus

- some muscles are also - some muscles are also attached to attached to humerus, radius and ulna.humerus, radius and ulna.

Extensor compartment muscles – origin and Extensor compartment muscles – origin and insertioninsertion

Tendons Tendons go to the hand go to the hand underunder

the extensor the extensor retinaculum.retinaculum.

Individual and combination actionsIndividual and combination actions

Extensors are essential for power of grip.Extensors are essential for power of grip.

Brachioradialis,Brachioradialis, Ext.carpi radialis Ext.carpi radialis longus,longus,

Ext.carpi radialis Ext.carpi radialis brevis,brevis,

Extensor digitorum, Extensor digitorum,

Extensor digiti minimi, Extensor digiti minimi,

Extensor carpi ulnaris, Extensor carpi ulnaris,

Anconeus,Anconeus,

Supinator,Supinator,

Abductor pollicis Abductor pollicis longus,longus,

Extensor pollicis Extensor pollicis longus,longus,

Extensor pollicis Extensor pollicis brevis,brevis,

Extensor indicis.Extensor indicis.

Motor innervation:Motor innervation: - - Radial Radial nerve supplies (main nerve);nerve supplies (main nerve); . Brachioradialis,. Brachioradialis, . Ext.carpi radialis longus.. Ext.carpi radialis longus.

- Nerve to medial head of triceps (given off in - Nerve to medial head of triceps (given off in spiral spiral groove)groove) supplies anconeus. – supplies anconeus. –

Posterior interosseous .N Posterior interosseous .N (branch of radial (branch of radial nerve)nerve). supplies rest of the muscles of the . supplies rest of the muscles of the posterior compartment of the forearm.posterior compartment of the forearm.

Radial .N Radial .N and Branches and Branches in the forearm; in the forearm;

- posterior interosseous .N- posterior interosseous .N

(deep branch)(deep branch)

- articular branches to - articular branches to radio-ulnar joint radio-ulnar joint

- radial nerve continues radial nerve continues as as

superficial branch to superficial branch to the dorsum of the hand.the dorsum of the hand.

Blood supply to extensor Blood supply to extensor compartmentcompartment

Posterior interosseous artery--- Posterior interosseous artery--- supplies supplies upper 2/3upper 2/3rdsrds

Anterior interosseous artery--- Anterior interosseous artery--- suppliessupplies

lower 1/3lower 1/3rdrd..

Region of the wristRegion of the wrist

-Carpal tunnel; -Carpal tunnel;

anterior aspect anterior aspect

-Extensor tendons; -Extensor tendons;

dorsal aspectdorsal aspect

-Anatomical snuff -Anatomical snuff box; box;

lateral aspect.lateral aspect.

Between forearm and hand.

Carpal tunnelCarpal tunnelSpace between Space between flexor retinaculumflexor retinaculum & & the carpal bones.the carpal bones.

Structures passing through the carpal tunnel; the carpal tunnel; -Median nerve,-Median nerve,-Tendons of:Tendons of: . Flexor digitorum superficialis,. Flexor digitorum superficialis, . Flexor digitorum profundus, . Flexor digitorum profundus, . Flexor pollicis longus.. Flexor pollicis longus.

Structures passing through the roof of carpal Structures passing through the roof of carpal tunnel;tunnel;

-The tendon of flexor carpi radialis -The tendon of flexor carpi radialis -The ulnar nerve -The ulnar nerve throughthrough Guyons tunnel. Guyons tunnel.

Carpal tunnel Carpal tunnel syndromesyndromeEffects of Effects of compression on compression on median nerve median nerve in the carpal in the carpal tunnel.tunnel.

Structures passing on the roof of the carpal Structures passing on the roof of the carpal

tunnel;tunnel; Tendon of palmaris longus,Tendon of palmaris longus, Palmar cutaneous branch of median nerve,Palmar cutaneous branch of median nerve, Superficial branch of radial artery.Superficial branch of radial artery. Ulnar artery,Ulnar artery, Superficial veins,Superficial veins,

Arterial blood supply in the region of the wristArterial blood supply in the region of the wrist

Anterior and posterior Anterior and posterior carpal arterial carpal arterial arches.arches.

The carpal branches of radial, ulnar, and anterior interosseous The carpal branches of radial, ulnar, and anterior interosseous arteriesarteries

The carpal arches communicate with dorsal metacarpal The carpal arches communicate with dorsal metacarpal arteries.arteries.

Veins- mainly via deep veins.Veins- mainly via deep veins.

Six compartments of ext. retinaculumSix compartments of ext. retinaculum, lateral to , lateral to medial:medial: Abductor pollicis longus,Abductor pollicis longus,Extensor pollicis brevis. 1Extensor pollicis brevis. 1stst Ext.carpi radialis longusExt.carpi radialis longusExt.carpi radialis brevis. 2Ext.carpi radialis brevis. 2ndnd

Ext.pollicis longus 3Ext.pollicis longus 3rdrd

Ext.digitorum Ext.digitorum Ext.indicis 4Ext.indicis 4thth Ext.digitiminimi 5Ext.digitiminimi 5thth

Ext.carpi ulnaris. 6Ext.carpi ulnaris. 6thth

BBounderies:ounderies:

Lateral,Lateral,

- abductor pollicis - abductor pollicis longus.longus.

- extensor pollicis - extensor pollicis brevis,brevis,

Medial,Medial,

- extensor pollicis - extensor pollicis longus.longus.

Anatomical snuff boxAnatomical snuff box- on the lateral - on the lateral aspect aspect

Floor Floor - base of 1st metacarpal- base of 1st metacarpal- scaphoid, scaphoid, - trapezium trapezium - styloid process of - styloid process of radius.radius.

Radial artery passes on the floor of anatomical- -snuff box.

RoofRoof of anatomical snuff box: - fascia and - fascia and skin.skin.Passing in the superficial fascia of the roof--

- cephalic vein - cutaneous branch of radial nerve.

Clinical aspectsClinical aspects

Deformities at the Deformities at the wristwrist

- Manus varus = Wrist is fixed in adduction,- Manus varus = Wrist is fixed in adduction,- Manus valgus = Wrist is fixed in abduction,- Manus valgus = Wrist is fixed in abduction,- Cystic swelling of synovial sheath-- - Cystic swelling of synovial sheath-- ganglionganglion- Wrist drop Wrist drop = = Damage toDamage to - radial nerve- radial nerve - posterior interosseous nerve.- posterior interosseous nerve.

- Injury to any structure.- Extention of hand infections into Parona’s space Etc.

Dinner fork deformity = Displaced fracture at wrist.Dinner fork deformity = Displaced fracture at wrist.

End of topic

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