Anatomy: The Neck, anatomy, Posterior Triangle of the Neck

Arteries of the Posterior Triangle of the Neck

The third part of the subclavian artery. The subclavian artery has 3 parts - separated by the scalenus anterior in thirds - the last third is the part between the scalenus anterior and the clavicle. It is a fingerbreath superior to the clavicle.

The transverse cervical artery arises from the thyrocervical trunk - a branch of the subclavian artery. The transverse cervical artery runs superficially and laterally across the posterior triangle, 2 to 3 cm superior to the clavicle.

The Suprascapular artery from the branch of the thyrocervical trunk - runs posterior to the clavical to the muscles around the scapula.

Artery: Transverse cervical artery
Superficial dissection of the right side of the neck, showing the carotid and subclavian arteries. Transverse cervical artery is labeled, branching from the thyrocervical_trunk.
Superficial and deep branches from the transverse cervical artery.
Latin	arteria transversa cervicis, arteria transversa colli
Gray's	subject #148 82
Supplies	Trapezius Sternocleidomastoid
Source	Thyrocervical trunk
Branches	Superficial branch Deep branch
Vein	Transverse cervical veins

Occipital artery is a branch of the external carotid artery enters the apex of the posterior triangle before ascending to the occipital area. 

Nerves in the posterior triangle. The Accessory nerve (CN XI) that divides the posterior triangle into a superior and inferior parts. The Accessory nerve is a motor nerve consisting of spinal (C1 to C5) and cranial roots. The spinal roots travel superiorly and enter the posterior cranial fossa through the foramen magnum. Here they join the cranial roots of the accessory nerve from the Medulla. Both combined roots leave the skull through the jugular foramen.

The Spinal roots separates immediately and supplies the Sternocleidomastoid muscle and the trapezius muscle.

Lesions to the Accessory Muscle are rare. The Accessory Nerve may be damaged by Traumatic injury, tumours to the base of the skull, fractures involving the jugular foramen, and neck lacerations. Presents with weakness in turning the head to the OPPOSITE site against resistance. Unilateral paralysis of the trapezius muscle is evident by the patients inability to elevate and retract the shoulder, and is unable to lift the arm above the horizontal level. Drooping of the shoulder is obvious.


The Accessory Nerve function can also be functionally impaired by inflamed lymph nodes in the neck. During surgical dissection of the neck lymph nodes care should be taken to isolate and preserve the  Accessory Nerve. 

Nerve: Accessory nerve
Plan of upper portions of glossopharyngeal, vagus, and accessory nerves.
Inferior view of the human brain, with the cranial nerves labelled.
Latin	nervus accessorius
Gray's	subject #206 913
Innervates	sternocleidomastoid muscle, trapezius muscle
MeSH	Accessory+Nerve

The Cervical Plexus


, Anterior triangle, Arteries, Carotid Artery, Carotid Body, , Hyoid Muscles, Muscles, Neck, Nerves, , Posterior triangle, raised JVP, , XI

Anatomy Neck. Superficial Structures of the Neck. Accessory Nerve, Anterior triangle, Arteries, Carotid Artery, Carotid Body, Cervical Plexus, Hyoid Muscles, Muscles, Neck, Nerves, Platysma, Posterior triangle of the Neck, raised JVP, Sternocleidomastoid, XI

Platysma Muscle is a wide, thin, subcutaneous sheet of striated muscle that is located in the superficial fascia of the neck. The platysma covers the superior part of the anterior triangle and the anteroinferior part of the posterior triangle of the neck. Its fibers blend with the facial muscles.  The Platysma is the muscle of facial expression.

Platysma muscle
Platysma is visible at bottom, in neck
Gray's	subject #110 387
Origin	subcutaneous tissue of infraclavicular and supraclavicular regions - Fascia and Skin over Pectoralis major and deltoid muscles
Insertion	base of mandible; skin of cheek and lower lip; angle of mouth; orbicularis oris
Artery	branches of the Submental artery and Suprascapular artery
Nerve	cervical branch of the facial nerve (CN VII)
Actions	Draws the corners of themouth inferiorly and widens it (as in expressions of sadness and fright). Also draws the skinof the neck superiorly whenteeth are clenched

 

An Raised JVP can be seen under the platysma Muscle.


Cervical branch of the facial nerve supplies the platysma - and may be damaged by malignant parotid or submandibular cancer (Ca). The cervical branch of the facial nerve may also be damaged by surgical procedures like the removal of a branchial cyst. Injury to the mandibular branch produces a noticeable facial deformity and damaged to the cervical branch of the facial nerve produces unsightly drooping neck. A gaping of the skin incision may be present after the removal of a thyroid - if the platysma edges were not sutured.

Nerve: Cervical branch of the facial nerve
Plan of the facial and intermediate nerves and their communication with other nerves. (Labeled at center bottom, as "Cervical".)
The nerves of the scalp, face, and side of neck. (Cervical labeled at center, in dark region under jaw.)
Latin	ramus colli nervi facialis
Gray's	subject #202 905
From	facial nerve