posterior triangle of the neck

Anatomy of the neck

Professor Dr. Mohamed El fiky

Professor of anatomy and Embryology

Cutaneous nerves

• The neck are supplied by the anterior rami of C2, 3 & 4 through the cutaneous branches of cervical plexus :u Lesser occipital (C2) uGreat auricular (C 2 & 3)uTransverse cervical (C 2 & 3)uSupraclavicular (C 3 & 4)

•

Superficial veins of the neck External jugular vein

• Course and relations :§ Begins behind the angle of mandible by the union of :

Ø Posterior auricular Ø Posterior division of posterior facial

vein.¡ It descends obliquely backwards across the sternomastoid¡ About 1 inch above the middle of the

clavicle it pierces the deep fascia to

• end in the subclavian vein. • Tributaries

1. Posterior auricular vein.2. Posterior division of the posterior facial vein 3. Posterior external jugular vein.4. Transverse cervical vein.5. Suprascapular vein.6. Anterior jugular veins.

Anterior jugular vein

• Begins below the chin and descends close to midline to the suprasternal notch where it joins its fellow forming jugular arch.

• The vein then bends sharply laterally deep to the sternomastoid to drain into the external jugular

Platysma Muscle

• It lies in the superficial fascia of the side of the neck.

• Origin: From the deep fascia covering the pectoral region.

• Insertion: Into the lower border of the mandible.

• Nerve supply: Facial nerve (Cervical branch).

• Action: Depresses the mandible and draws down the angle of the mouth .

Sternomastoid Origin: u Sternal head : from the superolateral part of the front of the

manubrium sierni. v Clavicular head : from the medial 1/3 of the superior surface of the

clavicle. Insertion : u Lateral surface of the mastoid process. v Lateral half of the superior nuchal line. Nerve supply: u Spinal accessory (motor).v Branches from ventral rami of C2,3 (sensory, proprioceptive). Actions: (A) When one muscle contracts:

u Turns the face to the opposite side. v Tilts the head towards the shoulder .(B) When both muscles contract together : flex the neck.

SternomastoidMuscle

Sternal Head

Clavicular Head

MastoidProcess

Superior Nuchal Line

Posterior triangle Boundaries : • Anterior : posterior border of sternomastoid.• Posterior : anterior border of trapezius. • Inferior(base) : intermediate of third of the clavicle • Apex : meeting of trapeziue and sternomastoidRoof : formed by • (1) skin; (2) superficial fascia and platysma (3) deep fascia Floor : formed by the following muslces from above downwards: (1) Semispinalis capitits (2) splenius capitis . (3) levator scapula (4) Scalenus posterior . (5) scalenus medius. • Division of the triangle: it is subdivided by the inferior belly of

mohyoid into: u Occipital triangle : the larger uper part.v Supraclavicular triangle : the smaller lower part.

Anterior Triangle of

The Neck

Posterior Triangle of

The Neck

Inferior belly ofOmohyoid Muscle

OccipitalTriangle

• Contents of the posterior triangle: • u Nerves : • Rootsandtrunksof • brachial plexus. • Branches of cervical • plexus • Spinalaccessory. • v Arteries: • Third part of subclavian. • Trnasverse cervical. • Suprascapular. • Occipital .

w Veins :a. Subclavian.b. Transverse cervical.c. Suprascapular.d. Lower part of the external jugular. xMuslces : inferior belly of omohyoid. y Lymph nodes: •Supraclavicular : along the lower part of the posterior border of the sternomastoid muscle. •Occipital : at the apex of the triangle.

1- Spinal accesory nerve

2- Branches of cervical plexus

3- Roots and trunks of the brachial plexus

4- Transverse cervical artery

5- Suprascapular artery

7- 3rd part ofsubclavian artery

6- Subclavian vein

Roots

Cords

Divisions

Trunks

anterior

posterior

Branches

C6

C7

C8

T1

Deep part ofExternal jugular vein

Semispinalis capitis

Splenius capitis

Levator Scapulae

Scalenus medius

Scalenus posterior

The floor of the triangleis covered by Deep layer of

investing cervical fascia

Torticollis