posterior triangle final

8/8/2019 Posterior Triangle Final

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Posterior triangle of the neck

and its applied aspect


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Contents

Boundaries

Contents

Muscles Nerves

Vessels

Lymphatics

Applied aspect


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SCM

divides the

neck Into

2 triangles

1-anterior

2-posterior


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Posterior Triangle of the Neck

Boundaries:

Base

Anterior border

Posterior border

Apex


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Roof1-skin

2-the superficial fascia

which containsa) platysma

b) external jugular vein

c) cutaneous branches

of the cervical plexus

3-the deep fascia


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Floor

1- splenius capitis

2- levator scapulae

3- scalenus posterior

4- scalenus medius5- scalenus anterior

All covered by

the prevertebral fascia

Small part of the semispinalis muscle may appear at

the apex of the triangle


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*subdivided by the inferior belly of the omohyoid muscle

Into : 1-occipital

2- subclavian triangles (supraclavicular)


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*ContentsA-Muscles the inferior belly of the omohyoid m


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B-nerves


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Vessels:

Arteries-Transverse cervical

vessels

-Suprascapular vessels-Subclavian artery

crossing the first rib

VeinsExternal jugular vein


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Muscles


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Platysma muscleOrigin

Insertion

Blood supply

Nerve supply

Action-depresses the mandible

-drawers down the lower lip


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Omohyoid muscle:Origin

Insertion

Nerve supply

Ansa Cervicalis (C1,2 and 3)

Action

depresses hyoid bone


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Nerves


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Nerves:


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Spinal Accessory Nerve

Course

Surface marking

Erbs point

Torticollis


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Torticollis


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The cervical plexus:-anterior primary rami of the upper four cervical nerves

-deep to the SCM-Each nerve except the first divides into upper and lower branches


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The cervical plexus:

*4Cutaneous Branches:1-lesser occipital nerve

2-great auricular nerve

3-Transverse cutaneousNerve of the neck

4-Supraclavicular nerve

May relay pain referred to the shoulder from the

phrenic nerve

Distribution Supplies the skin of thorax to the level

of second rib


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The cervical plexus:

*4 muscular branches:

a-prevertebral muscles C1-C4

b-levator scapulae m C3,C4

c-Scalenus ant.,med., and posterior

d-infrahyoid and geniohyoid ms. C1,C2,C3

e-phrenic nerve C3,C4,C5

f-SCM C2,C3 + Trapezius C3,C4

ONLY - Afferent (Propriception)

- Sympathetic fibers


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Phrenic nerve-C3,4,and 5, Mainly C4

1- motor innervationof the diaphragm

2- Sensory

A-pericardiumB- mediastinal pleura

C- pleural and

peritoneal

And coverings of the

central part of the

diaphragm


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The Brachial plexus:

*is formed by union of the anteriorprimary rami ofC5-T1

Surface markings:

Roots

Trunks

Cords


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The brachial plexus and subclavian artery may be

compressed in the neck by

a rudimentary cervical rib

a tight fibrous band

first thoracic rib

a tight scalenus anterior muscle

giving rise to sensory,

motor

vascular symptoms

in one or both upper extremities.


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Cervical rib

Pressure in the region of acervical rib will give rise to local

pain as well as pain referred tothe hand and arm particularly inthe ulnar portion of the hand andforearm since

There is muscular weakness ofthe small hand muscles.


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Birth Brachial Plexus Palsy

Pathogenesis

Prevalence

Total Prevalence:

0.2 - 2.5 / 1,000 births

Persistent Weakness:

0.4 - 5.0 / 10,000 births

The first recorded mention of it is by William

Smellie in a 1768 publication on midwifery.


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Upper Brachial Plexus (Erb's) Palsy

These infants cannot move the shoulder and keeptheir arms extended and turned inward, giving theappearance of the porter's tip hand."


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Lower Brachial Plexus (Klumpke's)

Palsy


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Vessels


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The veins:A. The subclavian vein(which lies on the scalenus

anterior muscle)

B. Two veins which end inthe external jugular vein

1- the transverse cervical vein2- the suprascapular vein


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- begins just behind the angle of the

mandible

- lies on a line joining the angle of

the mandible to the middle

of the clavicle

- deep to the platysma muscle

C-External jugular vein:


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Jugular venous pressure

External Jugular vein catheterization


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Subclavian artery

*Grooves the first rib as it passes between

- scalenus anterior

- scalenus medius muscles

*Is divided into 3 parts by the scalenus anterior muscle


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Subclavian artery

1-first parta. vertebral artery

b. thyrocervical trunk

c. internal thoracic artery

2-second part

*costocervical trunk

a. deep cervical arteryb. superior intercostal artery

first 2 post.intercostal artery

3-third part

*dorsal scapular artery

when it is present it replacesthe deep branch of the

transverse cervical artery


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*Transverse Cervical a.

-across the scalenus anterior mPhrenic n and trunks of the Br

plexus

-across the post.Triangle of the

Neck

*Suprascapular artery-across the scalenus anterior muscle and the Brachial plexus


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Applied aspect

Palpation and compression ofSubclavian

artery in patients with upper limb hemorrhage

Pleura and lung injuries in the root of the neck Cervical rib and Scalenus anticus syndrome

Dysphagia lusoria


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Battles sign - Occipital artery

Periauricular/ mastoid echymosis


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Superficial cervical LN

-lie along the external jugular vein in the

posterior triangle, and along the anterior

jugular vein in the anterior triangle

-superficial to the SCM

-Drains into deep cervical LN

-Receives Lymph vessels from the

occipital and mastoid LNs


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Neck Dissection

Level V

Posterior triangle of neck

Posterior border ofSCM

Clavicle

Anterior border oftrapezius

Va Spinal accessory

nodes

Vb Transverse cervical

artery nodesRadiologic landmark

Inferior border of Cricoid

Supraclavicular nodes


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Neck Dissection


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Neck Dissection


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Lateral Neck swellings

Differential Diagnosis:

Supraclavicular lymph nodes

Cystic Hygroma Pharyngeal pouch

Cervical rib

Subclavian aneurysm Lipoma


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Supraclavicular lymph nodes

Virchows node

Tuberculosis

Hodgkins disease

Head and neckMalignancy

Virchows nodes


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Cystic hygroma


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Pharyngeal pouch


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Subclavian Aneurysm


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References

Clinical Anatomy for medical students RichardSnell, 5th Ed.

Sicher and DuBRULs Oral anatomy, 8th Ed.

Students Grays anatomy Grants Method of Anatomy, A Clinical problem

solving approach, 11th Ed.

NMS Clinical anatomy Ernest April, 3rd Ed.

Stell & Marans Head and Neck surgery, 4th Ed.

B D Chaurasias Human anatomy, Volumes 1 & 3

A Concise textbook of surgery S Das, 3rd Ed.

P J Mehtas Practical Medicine

posterior triangle final

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