Posterior Triangle of the Neck Dr Zeenat Zaidi

Posterior Triangle of the Neck Dr. Zeenat Zaidi

The Neck n The region of the body that lies between: § The lower border of mandible & § The suprasternal notch and the upper border of the clavicle

Skin n The natural lines of cleavage are constant and run almost horizontally around the neck (an incision along a cleavage line heals as a narrow scar)

Superficial Fascia n Thin layer of connective tissue n Encloses platysma n Contains: » cutaneous nerves » superficial veins » superficial lymph nodes

Cutaneous Nerves n Back of the neck: • Greater occipital: branch of the posterior ramus of the C 2 (C 1 has no cutaneous branch) n Front & side of neck: Anterior rami of C 2 -C 4 through branches of cervical plexus • • Lesser occipital C 2 Great auricular C 2 -3 Transverse cutaneous C 2 -3 Supraclavicular C 3 -4

Superficial Veins External Jugular n Anterior Jugular n ØFormation ØCourse & relations ØTermination ØTributaries

Platysma n n Origin: Deep fascia covering pectoralis major and deltoid muscles Insertion: • Lower margin of the body of mandible • Some fibers blending with the muscle at the angle of the mouth (risoreus) • Below the chin, fibers interdigitate with the fibers of the opposite muscle Nerve Supply: Cervical branch of the facial nerve Action: Depresses mandible, draws down the lower lip and the angle of mouth

Superficial Lymph Nodes

Deep Cervical Fascia

Triangles of the Neck

Sternocleidomastoid n n Origin: Upper part of manubrium & medial third of clavicle Insertion: Mastoid process & lateral part of superior nuchal line Nerve supply: Spinal part of accessory nerve (motor) & ventral rami of C 2 -3 (proprioceptive) Action: • Both muscles acting together extend head at atlanto-occipital joint, and flex cervical part of vertebral column • Contraction of one muscle moves the face to the opposite side

Boundaries n n n Anterior: Posterior border of sternocleidomastoid Posterior: Anterior border of trapezius Inferior: Middle third of clavicle Roof: skin, superficial fascia, platysma, investing layer of deep fascia Floor: muscles covered by prevertebral fascia

Muscular Floor of the Posterior Triangle From above downward: § Semispinalis capitis § Splenius capitis § Levator scapulae § Scalenus medius § Scalenus anterior may not be present

Subdivision of the Posterior Triangle n Subdivided by the inferior belly of omohyoid muscle, into: § Large occipital triangle above § Small supraclavicular triangle below

Omohyoid Muscle n n Two bellies: Superior & Inferior joined by intermediate tendon Attachement: Superior belly to inferior border of hyoid bone, Superior belly Inferior belly to superior border of scapula & suprascapular Intermediate tendon ligament The Intermediate tendon lies deep. Inferior belly to sternocleidomastoid, connected to clavicle & the first rib by a loop of deep fascia Nerve supply: Ansa cervicalis Action: Depresses the hyoid bone (C 1, 2, 3)

Contents n Arteries: § Subclavian (3 rd part) § Superficial cervical & suprascapular (branches of thyrocervical trunk, a branch of 1 st part of subclavian artery § Occipital, a branch of external carotid artery

n Veins: n External jugular vein § § § Formation Termination Tributaries

n Nerves: § Branches of cervical plexus § Spinal part of accessory nerve § Brachial plexus

Clinical Notes n Torticollis (wry neck): § Congenital: due to excessive stretching of sternocleidomastoid muscle during labor. § Spasmodic: usually psychogenic n n Injury to spinal part of accessory nerve Injury to brachial plexus Pleura & Lung injuries in the root of neck Injury to nerve to platysma

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