1

The side of the neck is roughly quadrilateral in outline.

It is bounded

Anteriorly by –Anterior Median Line

Posteriorly- Anterior border of Trapezius

Superiorly- Base of the Mandible, a line joining angle of the mandible & mastoid process, superior nuchal line.

Inferiorly- Clavicle

This quadrangular space is divided obliquely by SCM muscle into anterior and posterior triangles

2

STERNOCLEIDOMASTOID

Origin:

a) Sternal head

b) Clavicular head

Insertion:

a) Lateral process of mastoid process

b) Lateral half of the superior nuchal line of occipital bone

Nerve Supply:

Spinal Accessory Nerve

Blood Supply:

One br from sup thyroid A. and suprascapular A.

Two br from occipital A.

3

STERNOCLEIDOMASTOID

One of the most important landmark in neck.

Actions-

When one muscles contracts-

When both muscles contracts

To make scm taut on one side, the pt is asked to turn the head to opp. side against resistance.

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PLATYSMA

It is a subcutaneous muscle forming a wide, thin fleshy sheet running upwards and medially in the neck from deltoid and pectoral fasciae to the base of mandible.

Supplied by cervical br. of facial nerve.

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ANTERIOR TRIANGLE OF NECK

Boundaries:

Medially: Ant median plane of neck

Laterally: SCM

Superiorly: Base of the mandible and a line joining the angle of the mandible n mastoid process

Subdivisions:

The ant triangle is subdivided by the digastric belly and sup belly of omohyoid into:

a) Submental

b) Digastric

c) Carotid and

d) Muscular Triangles

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ANTERIOR TRIANGLE -SUBDIVISONS

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8

SUBMENTAL TRIANGLE

This is a median triangle.

Boundaries:

Either side- Anterior belly of corresponding digastricmuscles

Base- Body of hyoid bone

Apex- at the chin

Floor- Rt and Lt Mylohyoid muscle

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CONTENTS OF SUBMENTAL TRIANGLE

It contains:

one or two lymph glands, the submental lymph nodes

some small veins; the latter unite to form the anterior jugular vein

The lymph nodes of the submental triangle receive lymph from the skin of the chin, the lower lip, the floor of the mouth, and the tip of the tongue. They send lymph to the submandibular and jugular chains of nodes. They belong to Level 1 gr of LNs

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DIGASTRIC TRIANGLE The submandibular triangle

(or submaxillary or digastrictriangle) corresponds to the region of the neck immediately beneath the body of the mandible.

Boundaries:

Anteroinf: Ant belly of digastric

Posteroinf: Post belly of digastric and stylohyoid.

Superiorly: Base of the mandible.

Roof : Skin, superficial fascia with platysma muscle, deep fascia

Floor: Mylohyoid anteriorly and hyoglossus posteriorly, part of middle constrictor.

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FLOOR OF DIGASTRICTRIANGLE

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CONTENTS OF DIGASTRIC TRIANGLE

ANTERIOR PART OF TRIANGLE

Strucures superficial to mylohyoid are:

Superficial part of submandibular gland, Facial vein , Subman. LN (belong to Level 1 gr of LNs), Facial A.,Submental A., Mylohyoidnerve and vessels.

Structures superficial to hyoglossus: Subman.gland,Intermediatetendon of digastric and stylohyoid, Hypoglossal N.

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CONTENTS OF DIGASTRIC TRIANGLE

POSTERIOR PART OF TRIANGLE:

Superficial Structures: Lower part of parotid, ECA before it enters parotid.

Deep structures: Styloglossus, stylopharyngeus, glossopharyngeal N, Pharyngeal br of vagus, Styloid process, a part of parotid

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CONTENTS OF POSTERIOR PART OF DIGASTRIC TRIANGLE

Deepest structures:

a) Internal carotid A.

b) Internal jugular vein

c) Vagus N.

• Submandibular LNs: Belong to Level 1 gr of LNs

• Clinically important because of their wide area of drainage. They are very commonly enlarged.

• They drain: a) center of forehead

b) Nose with Max. Frontal & Ethmoid sinuses

c) Inner canthus of the eye

d) Upper lip and the ant part of cheek with adjoinin gums

e)Outer part of lower lip with gums and teeth excluding incisors

f)Ant 2/3rd of tongue and floor of mouth

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CAROTID TRIANGLE Boundaries:

Anterosup: Post belly of digastric

Anteroinf: Sup belly of omohyoid

Posteriorly: Ant border of SCM

Roof: skin, superficial fascia, investing layer of deep fascia

Floor: Thyrohyoid M, hyoglossus, Middle and Inf. constrictors of pharynx

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CONTENTS OF CAROTID TRIANGLE

ARTERIES:

Common caortid A. with carotid sinus and carotid body at its termination

Internal carotid A.

External carotid A. with br.-

Ant br-sup thyroid, lingual facial

Post br- Occipital , post. Auricular

Medial- Asc. Pharyngeal

Terminal –Maxillary , Superficial Temporal.

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CONTENTS OF CAROTID TRIANGLE

VEINS:

Internal Jugular V.

Common Facial V.

Pharyngeal V

Lingual V. all draining in to internal jugular vein directly or via facial vein

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CONTENTS OF CAROTID TRIANGLE

NERVES:

Vagus running vertically downwards

Sup L.N of vagus dividing into ext n int L.N

Spinal Accessory N

Hypoglossal N

Sympathetic chain

Carotid sheath and its contents

Lymph Nodes: Jugulo-digastric and jugulo-omohyoid

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CONTENTS OF CAROTID TRIANGLE

ACCESSORY N.HYPOGLOSSAL N.

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COMMON CAROTID ARTERIES

Right common carotid artery is a branch of the brachiocephalicartery.It begins in the neck behind the right sternoclavicular joint.

Left common carotid artery is a branch of the arch of aorta.Itascends to the back of the left sternoclavicular joint and enters the neck.

In the neck,each artery runs upwards within the carotid sheath,under cover of the anterior border of the sternocleidomastoidmuscle.

CAROTID SHEATH Carotid sheath is condensation

of the fibroareolar tissue around the main vessels of the neck.

CONTENTS:It contains the common and internal carotid arteries,internal jugular vein and the vagus nerve.

In the sheath,common carotid artery is medially placed.Vagusnerve lies in between.

RELATIONS

The ansa cervicalis lies embedded in the anterior wall of the carotid sheath.

The cervical sympathetic chain lies behind the sheath.

BIFURCATION OF COMMON CAROTID ARTERY Common carotid artery

bifurcates into external and internal carotid arteries at the level of upper border of the thyroid cartilage.

Two structures of importance at the bifurcation are

Carotid sinus

Carotid body

CAROTID SINUS AND BODY

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CAROTID SINUS Carotid sinus is slight dilatation at the termination of the common

carotid artery or the beginning of the internal carotid artery.

It receives a rich innervation from the glossopharyngeal and sympathetic nerves.

FUNCTION:

Carotid sinus acts as a baroreceptor or pressure receptor and regulates pressure.

APPLIED ANATOMYCAROTID SINUS SYNDROME

Loss of consciousness due to simple head movements.

Hypersensitivity of the carotid sinus due to an unknown etiology.

Sudden slight pressure changes, such as that occasioned by movement of the head, may result in stimulation of the carotid sinus.

Impulses transmitted by the sinus reduce blood pressure and slow the pumping action of the heart.

Thus decreasing blood supply to the brain and resulting in sudden loss of consciousness.

While supporting the mandible care should be taken not to apply pressure on the carotid sinus.

CAROTID BODY Carotid body is a small,oval reddish-brown structure situated

behind the bifurcation.

It receives nerve supply mainly from the glossopharyngeal nerve, but also from the vagus and sympathetic nerves.

FUNCTION:

Carotid body acts as a chemoreceptor and responds to changes in the oxygen and carbon dioxide and Ph content of the blood.

EXTERNAL CAROTID ARTERY

Generally,it lies anterior to the internal carotid artery.

It is the chief artery of supply to structures in the front of the neck and in the face.

COURSE ECA begins in the carotid

triangle at the level of upper border of thyriod cartilage opposite the disc between the third and fourth cervical vertibrae.

In the carotid triangle,it lies under cover of the anterior border of the sternocleidomastiod muscle

As the artery ascends ,it passes deep to the post. Belly of digastric and stylohyoid muscle and terminates behind the neck of the mandible by dividing into the maxillary and superficial temporal arteries.

Has slightly curved course,so that it is anteromedial

to ICA in it lower part,and anterolateral to the ICA

in its upper part.

RELATIONSIN THE CAROTID TRIANGLE

Superficially—Cervical branch of facial nerve

Hypoglossal nerve

Facial,lingual,and superior

thyriod veins

Deep to the artery— Wall of pharynx

Superior laryngeal nerve

Ascending pharyngeal artery

ABOVE THE CAROTID TRIANGLE

Lies deep in the substance of the parotid triangle.

Within the gland, it is related

Superficially—Retromandibular vein

Facial nerve

Deep to the artery—ICA

Structures passing between ECA and ICA

Styloglossus

Stylopharyngeus

IXth nerve

Pharyngeal branch of

Xth nerve

Styloid process

BRANCHES OF EXT.CAROTID ARTERY

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ANTERIOR BRANCHES

SUPERIOR THYRIOD ARTERYORIGIN:Arises from the front of ECA

below the tip of greater cornua of hyoid bone.

COURSE: Runs downwards and forwards parallel and just superficial to the extenallaryngeal nerve.

- It passes deep to omohyoid ,sternohyoid, sternothyroid and reaches the upper pole of lateral lobe of thyroid and divides into its terminal branches.

It is accompanied by same-named vein.

BRANCHES:

INFRAHYOID ARTERY

STERNOCLEIDOMASTOID ARTERY

SUPERIOR LARYNGEAL ARTERY

CRICOTHYROID ARTERY

GLANDULAR BRANCHES

APPLIED ANATOMY The arch of superior thyroid artery is characteristic – diagnostic landmark

The artery and external laryngeal nerve are close to each other higher up, but diverge slightly near the gland.

- So, ligature of superior thyroid artery in thyroid surgery should be made close to the gland in order to avoid injury of the external laryngeal nerve.

-Damage to the external laryngeal nerve causes some weakness of phonation due to loss of tightening effect of the cricothyriod on the vocal cord.

Intra-arterial infusion chemotherapy for laryngeal and hypopharyngealcancers.

LINGUAL ARTERYORIGIN:Arises from ECA opposite the

tip of the greater cornua of hyoid bone.

-It may arise in common with the facial artery, then becoming the linguofacialtrunk.

COURSE:Divided into three parts by hypoglossus muscle.

FIRST PART – In carotid triangle, extends from origin to the posterior border of hyoglossus.

- Rests on the middle constrictor,formsa upward loop which is crossed by hypoglossal nerve. This loop permits the free movements of the hyiod bone.

SECOND PART – Deep to hyoglossus, runs horizontally forward along the upper border of hyoid bone between hyoglossuslaterally and middle constrictor, stylohyoid ligament medially.

THIRD PART [ ‘arteria profundalinguae’ ]—Also called as deep lingual artery.

-It runs upwards along the anterior Border of hyoglossus, then horizontally forwards on the undersurface of tongue on each side of frenum linguae.

-In vertical course,it lies b/t the genioglossus medially & inferior longitudinal muscle of tongue laterally. Horizontal part is accompanied by lingual nerve.

BRANCHES

SUPRAHYOID ARTERY

DORSAL LINGUAL ARTERY

SUBLINGUAL ARTERY

DEEP LINGUAL ARTERY

FACIAL ARTERYORIGIN: Arises from the ECA just above the tip of greater cornua

of hyoid bone.

COURSE: Runs upwards in -- neck as cervical part ; face -- facial part.

Tortuous course—In neck allows free movements of pharynx during deglutition,

on face -- free movements of mandible , lips, & cheek during mastication & facial expressions, escapes traction & pressure during movements.

.

Cervical part : Cervical part Runs upwards on superior constrictor of pharynx deep to the posterior belly of digastric.

-It grooves the posterior border of submandibular gland, makes S-bend [2 loops] 1st winding down over submandibular gland & then up over the base of mandible.

Facial part:The vessel enters the face by winding around the base of the mandible, and by piercing the deep cervical fascia,at the anteroinferior angle of the masseter muscle.

It runs upwards and forwards deep to the risorus, to a point 1.25cm lateral to the angle of the mouth.

Then it ascends by the side of the nose upto the medial angle of the eye where it terminates by anastomosing with the dorsal nasal branch of the ophthalmic artery.

BRANCHES

CERVICAL PART:

ASCENDING PALATINE ARTERY

TONSILLAR A RTERY

GLANDULAR ARTERIES

SUBMENTAL ARTERY

FACIAL PART:

INFERIOR LABIAL ARTERY

SUPERIOR LABIAL ARTERY

LATERAL NASAL ARTERY

ANGULAR ARTERY

POSTERIOR BRANCHES

OCCIPITAL ARTERYORIGIN:Arises in carotid triangle

from posterior aspect of ECA ,opposite the origin of facial artery.

-It is crossed at its origin by hypoglossal nerve.

COURSE: Passes backwards and upwards along & under cover of lower border of post. Belly of diagastric , crossing carotid sheath, hypoglossal & accessory nerves.

Then it runs deep to the mastiodprocess and muscles attached to it i.e.,sternocleidomastiod,

digastric etc.

Then crosses the rectus capituslateralis,superior oblique,andsemispinalis capitus muscle at the apex of the posterior triangle.

Finally it pierces the trapezius muscle and ascends in a tortuous course in the superficial fascia of the scalp.

Its terminal portion comes to lie along the greater occipital nerve.

BRANCHES

STERNOMASTOID BRANCHES

AURICULAR BRANCH

MASTOID BRANCH

MENINGEAL BRANCH

MUSCULAR BRANCH

POSTERIOR AURICULAR ARTERYORIGIN: Arises from the posterior

aspect of the external carotid artery just above the posterior belly of the digastric.

COURSE:It runs upwards and backwards deep to parotid gland, but superficial to the styloidprocess.It crosses the base of the mastiod process and ascends behind the auricle.

BRANCHES

Stylomastoid.

Auricular

Occipital.

MEDIAL BRANCH

ASCENDING PHARYNGEAL ARTERY

ORIGIN:The smallest branch arising from the medial side of the external carotid artery, near its commencement.

COURSE: Ascends vertically between the internal carotid and the side of the pharynx, to the under surface of the base of the skull, lying on the Longuscapitis.

BRANCHES

PHARYNGEAL BRANCHES

PALATINE BRANCH

PREVERTEBRAL BRANCHES

INFERIOR TYMPANIC ARTERY

MENINGEAL BRANCHES

TERMINAL BRANCHES

MAXILLARY ARTERYORIGIN:Large terminal branch given

off behind the neck of the mandible.

COURSE: Divided into three parts by lateral pterygiod muscle.

The first or mandibular portionpasses horizontally forward, between the ramus of the mandible and the sphenomandibular ligament, where it lies parallel to and a little below the auriculotemporal nerve; it crosses the inferior alveolar nerve, and runs along the lower border of the lateral pterygiod.

The second or pterygoid portion runs obliquely forward and upward superficial to the lower head of the lateral pterygiod.

The third or pterygopalatine portion passes between the two heads of the lateral pterygiod and pterygomaxillary fissure,to enter into the pterygopalatine fossa where it lies in front of the sphenopalatine ganglion.

BRANCHESFirst or Mandibular Portion

Deep Auricular.

Anterior Tympanic.

Middle Meningeal

Accessory Meningeal

Inferior Alveolar.

Second or Pterygoid Portion

Deep Temporal.

Masseteric.

Pterygoid.

Buccinator.

Third or Pterygopalatine

Portion

•Posterior Superior

Alveolar.

•Infraorbital.

•Greater palatine artery

•Pharyngeal.

•Aretry of pterygiod canal

•Sphenopalatine.

SUPERFICIAL TEMPORAL ARTERYORIGIN: The smaller of the two terminal branches of the external

carotid, appears, to be the continuation of ECA. It begins in the substance of the parotid gland, behind the neck of the mandible.

COURSE: It runs vertically upwards crossing over the root of the zygomatic process

-about 5 cm. above this process it divides into two branches, a frontal and a parietal.

Relations.—As it crosses the zygomatic process, it is covered by the Auricularis anterior muscle, and by a dense fascia; it is crossed by the temporal and zygomaticbranches of the facial nerve and one or two veins, and is accompanied by the auriculotemporalnerve, which lies immediately behind it.

BRANCHESBesides some twigs to the parotid gland, to the

temporomandibular joint, and to the Masseter muscle,

its branches are:

Transverse Facial.

Anterior Auricular.

Middle Temporal.

Frontal.

Parietal

MUSCULAR TRIANGLE

Boundaries Anteriorly: midline of neck

Superiorly: superior belly of omohyoid.

Inferiorly: anterior border of

sternomastoid .

Contents

Sternohyoid muscle

Sternothyroidmuscle

Thyrohyoid muscle

STERNOHYOID

Origin :Back of manubrium & medial end of clavicle.

Insertion :Medial part of the lower border of hyoid bone.

Nerve supply : AnsaCervicalis

Action: Depression of hyoid bone

STERNOTHYROID

Origin :Back of manubrium sterni.

Insertion: Oblique line of thyroid cartilage.

Nerve supply : Ansacervicalis.

Action :Depression of the larynx.

THYROHYOID

Origin: Oblique line of the thyroid cartilage.

Insertion :Lower border of hyoid bone.

Nerve supply :hypoglossal nerve(C1fibers).

Action:Depression of hyoid or elevation of larynx.

INFRAHYOID / STRAP / RIBBON MUSCLES

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SUPRAHYOID MUSCLESMUSCLE ORIGIN INSERTIO

N

NERVE

SUPPLY

DIGASTRIC Anterior belly from

digastric fossa

Post belly from

mastoid notch

Intermediate

tendon held by a

pulley to hyoid

bone

Ant belly by nerve

of mylohyoid

Post belly by facial

nerve

STYLOHYO

ID

Posterior surface

of styloid process

Junction of body

and greater

cornua of hyoid

bone

Facial nerve

MYLOHYOI

D

Mylohyoid line of

mandible

Body of hyoid

bone

Two m. muscle

of both side form

median raphe

Nerve to

mylohyoid

GENIOHYO

ID

Inferior mental

spine(Genial

tubercle)

Ant surface of

body of hyoid

bone

C1 thru

hypoglossal nerve71

INFRAHYOID MUSCLESMuscle Origin Insertion Innervation

Sternohyoid Post surface

of manubrium

sterni

Medial part of

lower border of

hyoid bone

Ansa cervicalis

Sternothyr

oid

-Post surface

of manubrium

sterni

Oblique line on

lamina of

thyroid

cartilage

Ansa cervicalis

Thyrohyoid Oblique line

on lamina of

thyroid

cartilage

Body and greater

cornua of hyoid

bone

C1 thru

hypoglossal N

Omohyoid

Sup and inf

bellies

Upper border

of scapula

near

suprasternal

notch

Lower border of

body of hyoid

bone

Ansa cervicalis

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SUPRAHYOID MUSCLES 73

Table of Muscles

Muscle Origin Insertion Action Nerve Supply

Sternohyoid sternum hyoid ansa

OmohyoidSuprascapular notch

hyoid ansa

SternothyroidBelow sternohyoid on manubrium

Thyroid cartilage oblique line

ansa

ThyrohyoidThyroid cartilage oblique line

hyoid C1-C2 (ansa)

Anterior Belly Digastric

-----intermediate tendon------

Inner surface of mandile

Trigeminal nerve

Posterior BellyDigastric

Medial aspect of the mastoid process

-intermediate tendon-

Facial nerve

MylohyoidMylohyoid line of mandible

Hyoid boneTrigeminal nerve

Hyoglossus Hyoid boneLateral side of tongue

hypoglossal

Stylohyoid Styloid process hyoid Facial nerve

ANSA CERVICALIS

Also known as AnsaHypoglossi.

This is a thin nerve loop that lies embedded in the ant wall of carotid sheath.

FORMATION:

Superior Root:continuationof descending br of hypoglossal N.

Inferior Root: 2nd and 3rd

cervical spinal N.

• Supplies Infrahyoid muscles.

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ANSA CERVICALIS

Def It is a loop of cervical nerves which lies on the surface of carotid sheath.

It is formed by the union of:

Descending hypoglossi :consist of fibers from C1.

Descending cervicalis : consist of fibers from C2&C3

Branches:

•Sternohyoid

•Sternothyroid

•Omohyoid(both belies)

POSTERIOR TRIANGLE

The boundaries are:

Anterior: Post. Border of SCM

Posterior: ant border of the trapezius muscle (Fig. 1-21)

Inferior or Base: Middle 1/3rd

of clavicle

Apex: Lies on the sup nuchalline where scm and trapeziusmeet.

Roof: Investing layer of the deep cervical fascia, ext jugular vein

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ROOF OF POSTERIOR TRIANGLE

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FLOOR OF POSTERIOR TRIANGLE

Floor: prevertebral layer of deep cervical fascia, covering following muscles

a) Splenius capitus muscle,

b) Levator scapulae

c) Scalenus medius

d) Occassionally scalenusposterior

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SUBDIVISIONS OF POSTERIOR TRIANGLE OF NECK Subdivided by inf. belly of

the omohyoid into

a) Larger upper triangle-Occipital triangle

b) Smaller lower triangle-Supraclavicular or Subclavian triangle

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CONTENTS OF POSTERIOR TRIANGLE Nerves

• Accessory nerve

• Root, trunks of brachial plexus and their branches :

Nerves to rhomboideus(dorsal scapular n)

Nerves to serratus anterior(long thoracic n)

Nerves to subclavius

Suprascapular nerve

Cervical nerves

Greater occipital nerve

Great auriclular nerve

Lesser occipital nerve

Transverse cervical nerve of neck

Supraclavicular nerve

• 3rd and 4th cervical nerves supplying trapezius

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NERVES OF POSTERIOR TRIANGLE

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ARTERIES OF POSTERIOR TRIANGLE

Arteries

Occipital artery

Third part of subclavianartery & branches of subclavianartery

Suprascapular

Transverse cervical

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VEINS IN POSTERIOR TRIANGLE

Lower part of External jugular vein & its tributaries

Superficial cervical vein

Subclavianveinis lower down and not in the triangle

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LYMPH NODES OF POSTERIOR TRIANGLE

Supraclavicularlymph nodes are present on posteriorborder of sternocleidomastoid

Occipital nodes

The nodes of posterior triangle belong to 5th level of cervical LNs

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