Download 09. Posterior Triangle of the Neck2010-10-01 03

Posterior Triangle of the
Neck
Dr. Zeenat Zaidi
The Neck

The region of the
body that lies
between:
 The lower border of
mandible &
 The suprasternal
notch and the upper
border of the
clavicle
Skin
 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
 Thin
layer of connective tissue
 Encloses platysma
 Contains:
»cutaneous nerves
»superficial veins
»superficial lymph nodes
Cutaneous Nerves

Back of the neck:
• Greater occipital: branch of
the posterior ramus of the C2
(C1 has no cutaneous branch)

Front & side of neck:
Anterior rami of C2-C4
through branches of cervical
plexus
•
•
•
•
Lesser occipital C2
Great auricular C2-3
Transverse cutaneous C2-3
Supraclavicular C3-4
Superficial Veins
External Jugular
 Anterior Jugular

Formation
Course &
relations
Termination
Tributaries
Platysma


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




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 C2-3
(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





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
or may not be present
Subdivision of the Posterior
Triangle

Subdivided by the
inferior belly of
omohyoid muscle,
into:
 Large occipital
triangle above
 Small
supraclavicular
triangle below
Omohyoid Muscle




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
Inferior belly
The Intermediate tendon lies
deep to sternocleidomastoid,
connected to clavicle & the first
rib by a loop of deep fascia
Nerve supply: Ansa cervicalis Action: Depresses the hyoid bone
(C1,2,3)
Contents

Arteries:
 Subclavian (3rd part)
 Superficial cervical &
suprascapular
(branches of
thyrocervical trunk, a
branch of 1st part of
subclavian artery
 Occipital, a branch of
external carotid artery

Veins:

External jugular
vein
 Formation
 Termination
 Tributaries

Nerves:
 Branches of
cervical plexus
 Spinal part of
accessory nerve
 Brachial plexus
Clinical Notes

Torticollis (wry neck):
 Congenital: due to excessive
stretching of
sternocleidomastoid muscle
during labor.
 Spasmodic: usually
psychogenic




Injury to spinal part of
accessory nerve
Injury to brachial plexus
Pleura & Lung injuries in
the root of neck
Injury to nerve to platysma
Thank You
&
Good Luck