Anatomy Unit 2: The Neck

Front 1

Superior border of the neck

Back 1

mandible, mastoid process, inferior nuchal line, external occipital protuberance.

Front 2

Inferior borders of the neck

Back 2

Manubrium(jugular notch), clavicle, Acromion process of the scapula.

Front 3

Anterior aspects of the neck

Back 3

•At its midline is comprised of the following bone and cartilages from superior to inferior:
oHyoid bone
oThyroid cartilage with thyroid notch (Adam’s Apple)
oCricoid Cartilage
oTracheal Cartilages

Front 4

Sternocleidomastoid muscle

Back 4

Origin: manubrium of the sternum, medial 1/3 of the clavicle.
Insertion:Mastoid process of the temporal bone and superior nuchal line.

Front 5

Posterior triangle

Back 5

Boundaries: Sternocleidomastoid, trapezius, and middle third of clavicle
-The posterior triangle is also subdivided into the occipital triangle and the supraclavicular (subclavian) triangle

Front 6

the inferior head of the omohyoid muscle

Back 6

seperates the occipital triangle and the supraclaivical triangles.

Front 7

The floor (deepest portion) of the posterior triangle

Back 7

formed by the following prevertebral muscles and prevertebral fascia: Splenius capitis, levator scapulae, and scalene muscles (anterior, middle, and posterior)

Front 8

The roof (most superficial portion) of the posterior triangle

Back 8

formed by investing fascia (superficial layer of deep cervical fascia)

Front 9

Nerves and BV found in the posterior triangle

Back 9

-Accessory Nerve (XI) – the only real structure passing through this triangle, between investing and prevertebral fascias
-Brachial Plexus – formed by ventral primary rami of spinal nerves C5,C6,C7,C8 and T1
-Cervical Plexus – cutaneous branches
-Subclavian artery and branches
-Subclavian vein and tributaries

Front 10

Anterior triangles

Back 10

4: submandibular, submental, muscular and caratoid triangles. All bilateral except the submental. Boundaries: midline, mandibular and SCM.

Front 11

Mandibular (digastric) triangle

Back 11

The boundaries of the submandibular (diagastric) triangle are:
-Anterior and posterior bellies of diagastric muscle
-Mandible
-The floor of the submandibular triangle is the mylohyoid muscle
-The contents in the submandibular triangle are: submandibular gland, submandibular lymph nodes, submandibular ganglion and lingual nerve, facial artery and vein, and hypoglossal nerve

Front 12

Submental

Back 12

The boundaries of the submental triangle are:
Anterior bellies of both digastric muscles, Hyoid bone
-The floor is also the mylohyoid muscle
-Submental lymph nodes are found in this area

Front 13

Muscular triangle

Back 13

-The muscular triangle is bounded by:
Median plane of neck, Superior belly of omohyoid muscle, Sternocleidomastoid muscle
•The following are found in the muscular triangle:
oInfrahyoid muscles
oThyroid and parathyroid glands
oCarotid sheath and contents
oRecurrent laryngeal nerves
oThyroid and cricothyroid cartilages (2 major cartilages of the larynx)
oPharynx and esophagus
oTrachea

Front 14

Carotid

Back 14

•The carotid triangle is bounded by:
-Posterior belly of digastric muscle
-Sternocleidomastoid muscle
-Superior belly of omohyoid muscle
The contents of the carotid triangle are the:
Carotid sheath and contents,
-Common carotid artery and internal carotid artery
-Internal jugular vein
-Vagus nerve
-Cervical sympathetic chain
-Hypoglossal nerve and superior root of ansa cervicalis
-External carotid artery and five of its branches

Front 15

Innervation of the skin of the neck

Back 15

innervated (cutaneous innervation) by sensory branches of the cervical plexus (ventral primary rami of spinal nerves C2 to C4). These branches are named:
oLesser occipital nerve (C2)
oGreat auricular nerve (C2, C3)
oTransverse cervical nerve (C2,C3)
oSupraclavicular nerve (C3,C4)

Front 16

External jugular

Back 16

formed in region of the parotid gland and then crosses sternocleidomastoid to end in the posterior triangle by piercing investing fascia (**always found in relation to the great auricular nerve).
Its formed by the union of 2 veins: Posterior auricular (drains back of ear, Retromandibular.

Front 17

Anterior jugular

Back 17

begins in the submental triangle and then travels inferiorly in anterior triangle

Front 18

Omohyoid muscle

Back 18

-Origin: superior part of scapula just medial to the scapular notch
-Insertion: inferior border of the body of the hyoid
-Inferior belly and superior belly are joined by a tendinous structure

Front 19

Occipital triangle

Back 19

Boundaries: -Inferior belly of omohyoid
-Anterior surface of trapezius.
Main Contents:
-Part of external jugular brain
-Posterior branches of cervical plexus of nerves
-Accessory nerve
-Trunks of brachial plexus
-Transverse cervical artery
-Cervical lymph nodes

-Posterior surface of SCM

Front 20

Subclavian triangle

Back 20

Boundaries:
-Inferior belly of Omohyoid
-Middle third of clavicle
-Posterior surface of SCM
oMain Contents:
-3rd part of subclavian artery
-Part of subclavian vein
-Supraclavicular lymph nodes

Front 21

Greater Auricular nerve

Back 21

-Receives nerve fibers from ventral primary rami of C2 and C3
-Travels from the posterior margin of the SCM and obliquely across to the angle of the mandible (where the body and ramus meet)
Divides into: Facial, auricular and mastoid.

Front 22

Lesser Occipital nerves

Back 22

o Follows the posterior margin of the SCM and ends up on occipital scalp
o Innervates (sensory) auricle and occipital scalp
o Originates from C2

Front 23

Transverse cervical nerves

Back 23

Goes transversely across the neck
-Crosses SCM transversely and divides into ascending and descending branches
Supplies skin of neck
-Originates from C2 to C3
-Mainly deep to the platysma

Front 24

Supraclavical nerves

Back 24

o Originates from C3 and C4 ventral primary rami
o Travels inferiorly as trunk and divides into usually 3 branches:
 Medial branch  supplies surface of manubrium
 Intermediate branch  supplies 2nd rib
 Lateral branch  supplies shoulder area (deltoid)

Front 25

Anza cervicalis

Back 25

o Motor nerve complex formed from fibers of ventral primary ramus of C1-C3 (part of cervical plexus
o Innervates infrahyoid muscles
o This ansa is in the wall of the carotid sheath
o The superior rami is composed of nerve fibers of the ventral primary rami of C1 and C2.
o It travels with the hypoglossal nerve (cranial nerve XII) for a short distance but does not become a functional part of the nerve.

Front 26

Infrahyoid muscles

Back 26

four pairs of strap like muslces: sternohyoid, sternothyroid, thyrohyoid and omohyoid. They fix and or depress the hyoid bone during mastication, deglutination and speech.

Front 27

Splenius capitis

Back 27

origin: ligamentum nuchae,spinous process of C7-T4. Attaches: mastoid process of temporal bone n lateral 1/3 of superio rnuchal line of occipital bone. innervated dorsal prim rami, located immediately deep tpt he trapezius.

Front 28

Levator scapula

Back 28

origin: transversus process of c1-c4. inserts medial border of spine of scapula, innervated by c3-c5.

Front 29

Anterior scalene

Back 29

origin: transverse process of c3-c6. inserts: ridge n scalene tubercle of 1st rib,innervated: ventral prim rami c4-c6. found just deep to clav head of SCM.

Front 30

Middle scalene

Back 30

origin: transverse process of c2-c7.
inserts: 1st rib btwn tubercle and groove for subclavian artery.
innervation: ventral prim rami of c3-c8

Front 31

Posterior scalene

Back 31

origin:transverse process of c4-c6.
inserts:outer surface of 2nd rib.
innervation: ventral prim rami c5-c7.

Front 32

Ligamentem nuchae

Back 32

strong band of collagenous and elastic fibers along spines of cervical vertebrae.

Front 33

External Jugular Vein

Back 33

lies nxt to greater auricular nerve. begins in parotid and terminates in subclavian. it is formed from union of retromandibular and posterior auricular.

Front 34

Subclavian artery

Back 34

is divided into 3 parts by the anterior scalene. The 1st part is btwn origin and ant scalene. 2nd part: posterior to the anterior scalene. 3rd part: lateral to the anterior scalene and extends to the 1st rib.

Front 35

Part 1

Back 35

contents: internal thoracic artery(supplies thorax, lat to manubrium), vetebral artery(supplies brain, sp , c1-c7), thyrocervical trunk.

Front 36

Thyrocervical trunk

Back 36

supplies neck and thyroid and splits into 3 branches. Suprascapular: muscle and tissue of scapula, goes lat n post.
Transverse cervical: trapezium and scapula, goes posteriorly.
Inferior thyroid artery:vascularizes thyroid gland, esophagus, trachea,
pharynx, and larynx; gives off inferior laryngeal artery, ascending cervical artery, glandular branches,
tracheal, esophageal and pharyngeal branches.

Front 37

Part 2

Back 37

part tht travels deep into ant scalene muscle. called costocervical trunk- it branches off into superior intercostal(passes under the subclavian artery and descends inferiorly and gives off the 1st 2 posterior intercostal arteries) and deep cervical artery(ascends superiorly and vascularizes the posterior neck muscles. It anastamoses with the occipital artery).

Front 38

Part 3

Back 38

travels laterally and gets off more branch called dorsal scapular. travels thru brachial plexus then to scapula.

Front 39

Subclavian vein

Back 39

passes anterior to the ant scalene. joins int jugular to form brachiocephalic vein. The main tributary of the subclavian vein is the external jugular vein, although it can also receive the dorsal scapular and anterior jugular veins.

Front 40

Clavicle

Back 40

site of attachment for trapezius and sternocleiodmastoid muscle.

Front 41

Hyoid Bone

Back 41

small u shaped bone, consists of body, greater and lesser horn. suspended by ligaments and muscles btwn temporal bones and sternum.

Front 42

Typical cervical vetebra

Back 42

1.transverse process
2.transverse foramen
3.articular facets (superior and inferior)
4.Lamina
5.pedicle
6.body
7.vertebral foramen
8.spines (bifid)

Front 43

Atlas C1

Back 43

1.transverse process
2.transverse foramen
3.anterior and posterior arches
4.anterior and posterior tubercles
5.articular facets (superior and inferior)
6.facets for dens

Front 44

Axis C2

Back 44

1.dens
2.articular facets (superior and inferior)
3.transverse foramen
4.lamina
5.spinous process
6.vertebral foramen
7.body

Front 45

Viscera of the anterior neck

Back 45

larynx(thyroid cartilage, cricoid cartilage, thyrohyoid membrane n cricohyoid membrane), thyroid gland (left and right lobe, isthmus, pyrimidal lobe), parathyroid, trachea, esophagus.

Front 46

Common carotid artery

Back 46

• Main blood supply to brain
• When the common carotid artery reaches the highest point of the thyroid cartilage, the artery branches into its 2 terminal branches: the internal and external carotids. the bifurcation occurs at the carotid triangle.

Front 47

carotid sinus

Back 47

 The carotid sinus is a pressure receptor innervated by the glossopharyngial nerve (CN IX)

Front 48

carotid body

Back 48

oThe carotid body is a small oval-shaped structure located in the internal carotid artery immediately after this bifurcation
 The carotid body is a chemoreceptor that checks O2 and CO2 and is innervated by the glossopharyngeal and vagus nerves.

Front 49

Internal carotid artery

Back 49

• The internal carotid artery ascends the rest of the length of the neck WITHOUT giving off any branches until it reaches the skull

Front 50

External carotid artery

Back 50

oSuperior Thyroid Artery
oAscending Pharyngeal Artery
oLingual Artery
oFacial Artery
oOccipital Artery

Front 51

Superior thyroid artery

Back 51

o Infrahyoid artery  it travels just inferior to the hyoid bone, deep to the infrahyoid muscle and serves to vascularize the area.
oSternocleidomastoid branch  travels along the carotid sheath and supplies the SCM
oSuperior Laryngeal Artery  pierces through a small opening in the thyrohyoid membrane and enters the larynx
oCricothyroid Artery  a small branch that travels along and supplies the cricothyroid ligament and muscle.
 Anastamoses with its counterpart on the other side of the body and the inferior thyroid artery
oGlandular Branches  supply the thyroid and parathyroid

Front 52

Internal jugular vein

Back 52

oThe IJV drains blood from the brain, anterior face, cervical viscera, and deep muscles of the neck
oIt runs inferiorly through the neck in the carotid sheath with the internal carotid artery and the common carotid artery and vagus nerve

Front 53

Sternohyoid

Back 53

oLocation: Anteriolateral aspect of neck
oOrigin: manubrium and clavicle, sternoclavicular joint
oInsertion: medial to omohyoid and into body of hyoid
oFunction: depresses and stabilizes hyoid bone
oInnervation: Ansa Cervicalis

Front 54

Sternothyroid

Back 54

oDeep to sternohyoid
oOrigin: deep aspect of manubrium
oInsertion: Oblique line of thyroid cartilage
oFunction: depress the larynx by pulling thyroid cartilage down

Thyroid cartilage is the major cartilage of the larynx
oInnervation: Ansa Cervicalis

Front 55

Thyrohyoid

Back 55

oDeep to sternothyroid
oOrigin: Oblique line of thyroid cartilage
oInsertion: Greater horn and body of hyoid bone
oFunction: if hyoid is fixed, it elevates larynx
oInnervation: C1, via hypoglossal nerve
THIS IS THE ONLY INTRAHYOID muscle tht is NOT innervated by the ansa cervicalis.

Front 56

Omohyoid

Back 56

oLocation: posterior and anterior triangles of neck
oOrigin: Superior border of scapula
oInsertion: inferior border of body of hyoid bone
oInnervation: Ansa Cervicalis
oFunction: pulls down hyoid bone (depresses) and stabilizes it

Front 57

Right recurrent laryngeal nerve.

Back 57

•A branch of the right vagus,
which loops around the right subclavian and goes deep to the common carotid artery. It then goes behind the thyroid gland to enter the larynx from its inferior posterior aspect where it is called the inferior laryngeal nerve

Front 58

Inferior langeal nerve

Back 58

o Before it goes behind the thyroid, it reaches the tracheoesophageal groove and therefore it supplies the esophagus and the trachea
o This nerve provides sensory innervation infraglottic area and motor innervation to the intrinsic muscles except the cricothyroid
o This nerve also supplies the inferior constrictor muscle and the pharynx
o Surgeons must be careful not to incise the right recurrent laryngeal nerve when removing the thyroid because it is often embedded into the fascia around the parathyroid gland

Front 59

Superior langeal nerve

Back 59

mixed nerve tht gives 2 branches, internal laryngeal and external laryngeal.

Front 60

Internal laryngeal nerve

Back 60

Internal laryngeal nerve (sensory) which passes posterior to the external carotid artery and ALWAYS accompanies the superior laryngeal artery through the hole in the thyrohyoid membrane.
Thick nerve that innervates the larynx from the epiglottis to the vocal cord

Front 61

External laryngeal nerve

Back 61

 External Laryngeal Nerve (motor) follows the superior thyroid artery to innervate the cricothyroid muscle and the inferior constrictor muscle
 ** Cricothyroid is the only intrinsic muscle of the larynx to be innervated by a motor nerve

Front 62

Superior Ganglion

Back 62

periarterial: Internal Carotid Nerve ->carotid plexus on internal carotid artery
-External carotid nerve: plexus on external carotid artery , innervates everywhere the artery supplies

direct: Pharyngeal Nerve-> direct branch to pharyngeal plexus
Superior Cardiac Branch: direct branch to cardiac plexus

gray rami communicantes:
-gray rami c1- c4 rami spinal nerve.

Front 63

Middle ganglion

Back 63

C6 level, at level of cricoid cartilage
oDirect branches to trachea and esophagus
oMiddle Cardiac nerve
oGray rami to C5-C6 spinal nerves

Front 64

Inferior ganglion

Back 64

C7 level
oVertebral Branch  periarterial plexus around vertebral artery
oInferior Cardiac Nerve
oGray rami to C7-C8 spinal nerves

Front 65

Stellate gangion

Back 65

Sometimes inferior cervical ganglion fuses with the 1st thoracic ganglion to form a larger, star shaped ganglion