Posterior triangle of the neck

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Posterior triangle of the neck
Copy of Musculi coli base, my edits for tringles, labeled triangles,posterior.svg
Posterior triangle
Side of neck, showing chief surface markings. (Nerves are yellow, arteries are red.)
Latin Trigonum cervicale posterius
Trigonum colli posterius
Regio cervicalis posterior
TA A01.2.02.009
FMA 57778
Anatomical terminology

The posterior triangle (or lateral cervical region) is a region of the neck.


It has the following boundaries:

Apex: Union of the sternocleidomastoid and the trapezius muscles at the superior nuchal line of the occipital bone

Anterior: Posterior border of the sternocleidomastoideus

Posterior: Anterior border of the trapezius

Base: Middle one third of the clavicle

Roof: Investing layer of the deep cervical fascia

Floor:-(from above downward) 1.semispinalis capitis 2.spinalis capitis 3.levator scapuli 4.scleneus posterior 5.sclenues medius


The posterior triangle is crossed, about 2.5 cm above the clavicle, by the inferior belly of the omohyoid muscle, which divides the space into two triangles:


A) Nerves and plexuses:

B) Vessels:

C) Lymph nodes:

  • Occipital
  • Supraclavicular

D) Muscles:

Clinical significance[edit]

The accessory nerve (CN XI) is particularly vulnerable to damage during lymph node biopsy. Damage results in an inability to shrug the shoulders or raise the arm above the head, particularly due to compromised trapezius muscle innervation.

The Internal jugular vein's superficial location within the posterior triangle also makes it vulnerable to injury.

See also[edit]


This article incorporates text in the public domain from page 563 of the 20th edition of Gray's Anatomy (1918)

External links[edit]

  • lesson5 at The Anatomy Lesson by Wesley Norman (Georgetown University) (necktriangle)
  • lesson6 at The Anatomy Lesson by Wesley Norman (Georgetown University)
  • Anatomy figure: 24:01-02 at Human Anatomy Online, SUNY Downstate Medical Center - "Identification of the muscles associated with the posterolateral triangle."