Posterior Triangle of Posterior Triangle of the Neckthe Neck

Dr. Zeenat Zaidi

The NeckThe Neck The region of the The region of the

body that lies body that lies between:between: The The lower border lower border

of mandible of mandible && The The suprasternal suprasternal

notch notch and the and the upper upper border of the border of the clavicleclavicle

SkinSkin The natural The natural lines of cleavagelines of cleavage are are

constant and run almost constant and run almost horizontallyhorizontally around the neck (an around the neck (an incision along a cleavage line heals incision along a cleavage line heals as a narrow scar)as a narrow scar)

Superficial FasciaSuperficial Fascia Thin layer of connective tissueThin layer of connective tissue Encloses Encloses platysmaplatysma Contains:Contains:

»cutaneous nervescutaneous nerves

»superficial veinssuperficial veins

»superficial lymph nodessuperficial lymph nodes

Cutaneous NervesCutaneous Nerves Back of the neckBack of the neck: :

• Greater occipitalGreater occipital: branch of : branch of the posterior ramus of the C2 the posterior ramus of the C2 ((C1 has no cutaneous branchC1 has no cutaneous branch))

Front & side of neckFront & side of neck: : Anterior rami of C2-C4 Anterior rami of C2-C4 through branches of through branches of cervical cervical plexusplexus• Lesser occipital Lesser occipital C2C2

• Great auricular Great auricular C2-3C2-3

• Transverse cutaneous Transverse cutaneous C2-3C2-3

• Supraclavicular Supraclavicular C3-4C3-4

Superficial VeinsSuperficial Veins

External JugularExternal Jugular Anterior JugularAnterior Jugular

FormationFormationCourse & Course &

relationsrelationsTerminationTerminationTributariesTributaries

PlatysmaPlatysma Origin:Origin: Deep fascia covering Deep fascia covering

pectoralis major and deltoid pectoralis major and deltoid musclesmuscles

Insertion:Insertion:

• Lower margin of the body Lower margin of the body of mandibleof mandible

• Some fibers blending with Some fibers blending with the muscle at the angle of the muscle at the angle of the mouth (risoreus)the mouth (risoreus)

• Below the chin, fibers Below the chin, fibers interdigitate with the fibers interdigitate with the fibers of the opposite muscleof the opposite muscle

Nerve Supply: Cervical branch of the facial nerveAction: Depresses mandible, draws down the lower lip and the angle of mouth

Superficial Lymph NodesSuperficial Lymph Nodes

Deep Cervical FasciaDeep Cervical Fascia

Triangles of the NeckTriangles of the Neck

SternocleidomastoidSternocleidomastoid Origin:Origin: Upper part of manubrium & Upper part of manubrium &

medial third of claviclemedial third of clavicle Insertion:Insertion: Mastoid process & lateral Mastoid process & lateral

part of superior nuchal linepart of superior nuchal line Nerve supply:Nerve supply: Spinal part of accessory Spinal part of accessory

nerve (motor) & ventral rami of C2-3 nerve (motor) & ventral rami of C2-3 (proprioceptive)(proprioceptive)

Action:Action: • Both muscles acting together Both muscles acting together

extend head at atlanto-occipital extend head at atlanto-occipital joint, and flex cervical part of joint, and flex cervical part of vertebral columnvertebral column

• Contraction of one muscle moves Contraction of one muscle moves the face to the opposite sidethe face to the opposite side

BoundariesBoundaries Anterior:Anterior: Posterior border Posterior border

of sternocleidomastoidof sternocleidomastoid Posterior:Posterior: Anterior border Anterior border

of trapeziusof trapezius Inferior:Inferior: Middle third of Middle third of

clavicleclavicle Roof:Roof: skin, superficial skin, superficial

fascia, platysma, investing fascia, platysma, investing layer of deep fascialayer of deep fascia

Floor:Floor: muscles covered by muscles covered by prevertebral fasciaprevertebral fascia

Muscular Floor of the Muscular Floor of the Posterior TrianglePosterior Triangle

From above downward:From above downward: Semispinalis capitisSemispinalis capitis Splenius capitisSplenius capitis Levator scapulaeLevator scapulae Scalenus mediusScalenus medius Scalenus anterior may Scalenus anterior may

or may not be presentor may not be present

Subdivision of the Posterior Subdivision of the Posterior TriangleTriangle

Subdivided by the Subdivided by the inferior belly of inferior belly of omohyoidomohyoid muscle, muscle, into:into: Large Large occipitaloccipital

triangle abovetriangle above Small Small

supraclavicular supraclavicular triangle belowtriangle below

Omohyoid MuscleOmohyoid Muscle Two bellies:Two bellies: Superior & Inferior Superior & Inferior

joined by intermediate tendonjoined by intermediate tendon Attachement: Attachement: Superior belly Superior belly to to

inferior border of hyoid bone, inferior border of hyoid bone, Inferior belly Inferior belly to superior border to superior border of scapula & suprascapular of scapula & suprascapular ligamentligament

The The Intermediate tendon Intermediate tendon lies lies deep to sternocleidomastoid, deep to sternocleidomastoid, connected to clavicle & the first connected to clavicle & the first rib by a loop of deep fascia rib by a loop of deep fascia

Nerve supply:Nerve supply: Ansa cervicalis Ansa cervicalis (C1,2,3)(C1,2,3)

Superior belly

Intermediate tendon

Inferior belly

Action: Depresses the hyoid bone

ContentsContents Arteries: Arteries:

SubclavianSubclavian (3 (3rdrd part) part) Superficial cervical & Superficial cervical &

suprascapular suprascapular (branches of (branches of thyrocervical trunkthyrocervical trunk, a , a branch of branch of 11stst part of part of subclavian arterysubclavian artery

OccipitalOccipital, a , a branch of branch of external carotid arteryexternal carotid artery

VeinsVeins:: External jugular External jugular

veinvein FormationFormation TerminationTermination Tributaries Tributaries

Nerves:Nerves: Branches of Branches of

cervical plexuscervical plexus

Spinal part of Spinal part of accessory nerveaccessory nerve

Brachial plexusBrachial plexus

Clinical NotesClinical Notes Torticollis (wry neck):Torticollis (wry neck):

CongenitalCongenital: due to excessive : due to excessive stretching of stretching of sternocleidomastoid muscle sternocleidomastoid muscle during labor. during labor.

SpasmodicSpasmodic: usually : usually psychogenicpsychogenic

Injury to spinal part of Injury to spinal part of accessory nerveaccessory nerve

Injury to brachial plexusInjury to brachial plexus Pleura & Lung injuries in Pleura & Lung injuries in

the root of neckthe root of neck Injury to nerve to platysmaInjury to nerve to platysma

Thank You Thank You & &

Good LuckGood Luck