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N 15A

MA 584C

NECK- I

Lateral (Posterior) ! and Suboccipital !

Reading: Moore and Agur 583-596

M.Pizzimenti, Ph.D. OBJECTIVES:

• Identify the special characteristics of cervical vertebrae and describe the function of the

hyoid bone.

• Outline the borders and components of the triangles of the neck.

• Name and describe the muscles found in the posterior and anterior (sub) triangles of the

neck.

• Describe the principal sensory cutaneous nerves of the neck; describe area of cutaneous

innervation by these nerves; identify on a diagram the site of local anesthetic injection

that will produce the best results.

• Outline the layers of fascia of the neck, describe their location, function and contents.

• Describe the suboccipital triangle: List its borders and trace the course of the vertebral

a.,v.

• Describe and outline the clinical presentations of: torticollis, CN XI lesion, phrenic nerve

block, carotid endarterectomy, IJV jugular pulse, IJV puncture

Superficial Fascia

Deep to the skin and contains variable amount of fat, lymph vessels and nodes, nn., and platysma

m.

The Bony Skeleton of

the Neck

Cervical vertebrae:

• Seven in number

Typical features:

lamina, pedicle,

transverse process,

bifid spinous process

(C3-C6), foramina

transversarium

Atypical features:

Atlas (C1): anterior and posterior tubercles, no spinous process

Axis (C2): odontoid (dens) process

The hyoid bone:

U-shaped bone at C3 vertebral level

Body, and horns serve as the base for tongue and larynx.

Infrahyoid mm. attach here

Clavicle

See notes on upper extremity

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MA 587B

MA 584

Cranium

• Mastoid process of temporal bone

• Nuchal lines

• External occipital protuberance

Muscular Triangles (Regions) of the Neck

Sternocleidomastoid • Attaches from the mastoid process to clavicle and sternum

• Ipsilateral action:

• Bilateral action:

• Supplied by CN XI and transverse cervical a.

Lateral region (Posterior !)

• Posterior !

- Borders: posterior

sternocleidomastoid (SCM), ant.

border of trapezius, and clavicle.

- Investing fascia contributes to roof

- Deep cervical mm. contribute to floor

• Occipital & Omoclavicular (subclavian) !

- Constituents of posterior !

- Defined by the omohyoid m.

- Borders

! Occipital !

! Omoclavicular !

Anterior region (Anterior !)

• Borders: Anterior SCM, inf. Mandible, median line of neck

• Superficial fascia and platysma contribute to roof

• Pharynx, larynx, and thyroid gland contribute to floor

• Contains smaller constituent triangles (e.g.,

carotid, submental, submandibular, and muscular)

Superficial Structures within the Posterior !

Vasculature

• External Jugular v. (EJV)

- Travels vertically along SCM to drain into

the internal jugular v. (IJV) deep to SCM:

drains eventually into subclavian v.

- Formed by the joining of the retromandibular

and post. auricular v.

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MA 591A

MA 588

MA 584

Nerves

• Spinal accessory (CN XI)

- Motor supply to trapezius and

SCM

- Crosses ! approximately 1/3

of length of SCM from

mastoid process, runs along

levator scapulae

• Cutaneous branches of cervical

plexus

! Transverse cervical n. (C2 &

3): passes anterior to SCM,

deep to platysma and EJV;

sensory from anterior neck

! Great auricular n. (C2 &C3): ascends vertically, with the EJV, on SCM up to parotid

gland; sensory from post. auricle, skin over angle of mandible to mastoid process

! Lesser occipital n. (C2); travels along post. border of SCM; sensory from

posterior neck and scalp

! Supraclavicular nn. (C3 & C4); travels as a trunk deep to SCM and emerges

to send branches to shoulder and clavicle; sensory from this area.

! What would be the result of injecting an anesthetic agent at the point

where these nn. emerge? What would be lost?

! What would be the result of a lesion to the right CN XI?

! Describe torticollis

Deep Structures within the Posterior !

Muscles

• Splenius capitus m.

• Levator scapulae m.

• Anterior and Middle scalene mm.

- form interscalene triangle

- attach on transverse processes of C4-6 and on 1st rib

• Posterior scalene mm

- attach on transverse processes of C4-6 and on 2nd rib

! How might scalene mm. contribute to

respiration?

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MA 584

MA 598C

MA 584

Vasculature

Arteries: transverse cervical, suprascapular,

subclavian (3rd part), occipital a.

• Subclavian a.

• Thyrocervical trunk: branch of subclavian a.

- Transverse cervical a.

- Suprascapular a.

- Inferior thyroid a. (later)

• Occipital a.

- Recall posterior neck dissection

Veins

• External Jugular v.

! Recall course

! Can serve as an internal barometer to

detect increased venous pressure:

becomes distended along its course

• Internal Jugular v.

- Inferior portion just deep to SCM at junction of sternal and clavicular heads

- Drains into subclavian v.

- Access point

• Subclavian v.

- Travels ant. to ant. scalene m.

- Access point

Nerves

• Spinal accessory (CN XI)

- Motor supply to

• Ventral Rami of brachial plexus

- Contribution from spinal nn.

?

- Passes through interscalene !

with subclavian a.

• Suprascapular n.

• Long Thoracic n.

• Dorsal scapular n.

- Usually pierces middle scalene m.

• Phrenic n.

- Runs vertically and anterior to ant. scalene m.

- C3-C5 supplies _____________

• Sensory nn. from cervical plexus already studied

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MA 584

Deep Cervical Fascia of the Neck:

Overview

• Acts as a barrier to prevent spread of

infection; lies deep to superficial

fascia and divides into layers to

enclose specific components of the

neck.

• Support viscera

• Provides cleavage planes through

which tissues may be separated during

surgery

• Limits spread of infection

• Facilitates movement of structures of neck.

Layers of the Deep Fascia

• Investing Layer:

! Surrounds the cervical

vertebrae and all the viscera

and muscles of the neck.

! Restricts abscesses

immediately deep to it from

spreading to the surface.

! Superiorly attached to

zygomatic arch and inferiorly

to the clavicle. Posteriorly

continuous with ligamentum

nuchae.

• Prevertebral Layer:

- Extends from the base of the

skull down to the level of 3rd

thoracic vertebra.

- It envelops the cervical

vertebrae, the scalene

muscles, and the prevertebral and postvertebral muscles of the

neck.

- It forms floor of the post triangle.

• Pretracheal Layer:

- envelops the thyroid gland and covers larynx, trachea and part

of esophagus

- extends from the hyoid bone to the fibrous pericardium.

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• Retropharyngeal Space

! Lies between ___________ and ____________ layers

! permits movement of the pharynx, esophagus, larynx and trachea during swallowing.

• Carotid Sheath:

- sheath of deep cervical fascia that envelops the common and internal carotid arteries, the

internal jugular vein, the vagus nerve

- Cervical part of the sympathetic trunks lie embedded in loose connective tissue directly

posterior to the carotid sheath

Suboccipital Triangle

Deep to splenius and semispinalis capitus mm.

Muscles that comprise borders

Rectus capitus posterior major

Inferior oblique (capitus)

Superior Oblique (capitus)

Actions

Innervation

Other structures related to the area:

Greater occipital n (C2)

Vertebral a.

Rectus capitus posterior minor m.

MA = Moore, KL and Agur, AMR. 2007. Essential Clinical

Anatomy (3rd Ed), Lippincott Williams & Wilkins

MD = Moore, KL and Dalley, A. 1999. Clinically Oriented Anatomy (4th Ed), Lippincott Williams & Wilkins

GD = Tank, PW. 2005. Grant’s Dissector (13th Ed), Lippincott Williams & Wilkins

GA = Agur AMR and Dalley, A 2005. Grant’s Atlas of Anatomy (11th Ed), Lippincott Williams & Wilkins

N = Netter, FH. 2003, Atlas of Human Anatomy (3rd

Ed), Icon Learning Systems

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