Posterior triangle of the neck
The triangles of the neck. (Posterior triangles to the right. Sternocleidomastoideus runs vertically. Occipital triangle labeled at right, and subclavian triangle labeled at bottom.)
Side of neck, showing chief surface markings. (Nerves are yellow, arteries are red.)
Latin	regio cervicalis lateralis, trigonum cervicale posterius
Gray's	subject #145 563
Dorlands/Elsevier	r_07/12700361

The posterior triangle (or lateral cervical region) is bounded, in front, by the Sternocleidomastoideus; behind, by the anterior margin of the Trapezius; its base is formed by the middle third of the clavicle; its apex, by the occipital bone. Image File history File links Gray512. ... In human anatomy, the sternocleidomastoid (pronounced ) muscles are muscles in the neck that act to flex and rotate the head. ... Latin is an ancient Indo-European language originally spoken in Latium, the region immediately surrounding Rome. ... Elseviers logo Elsevier, the worlds largest publisher of medical and scientific literature, forms part of the Reed Elsevier group. ... In human anatomy, the sternocleidomastoid muscles are muscles in the neck that act to flex and rotate the head. ... Trapezius In human anatomy, the trapezius is a large superficial muscle on a persons back. ... Collarbone and collar bone redirect here. ... The occipital bone [Fig. ...

The space is crossed, about 2.5 cm. above the clavicle, by the inferior belly of the Omohyoideus, which divides it into two triangles: The omohyoid muscle is a muscle at the front of the neck that consists of two bellies separated by an intermediate tendon. ...

• an upper or occipital triangle
• a lower or subclavian triangle

It contains the accessory nerve, which crosses the triangle from the upper 1/3 of sternocleidomastoideus to the lower 2/3 of the trapezius. It is particularly vulnerable to damage at lymph node biopsy, where damage results in an inability to shrug the shoulders or raise the arm above the head (eg, for brushing hair)

External links

• Norman/Georgetown lesson6
• SUNY Figs 24:01-02 - "Identification of the muscles associated with the posterolateral triangle."
• Dictionary at eMedicine lateral+cervical+region

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant. Georgetown University, formally the The President and Directors of the College of Georgetown, is a private university in the United States, located in Georgetown, a historic neighborhood of Washington, D.C. Founded on January 23, 1789 by Archbishop John Carroll, it is both the oldest Roman Catholic and oldest Jesuit... The State University of New York Health Science Center at Brooklyn, better known as SUNY Downstate Medical Center, is an academic medical center and is the only one of its kind in the Borough of Brooklyn in New York City. ... eMedicine is an online clinical medical knowledge base that was founded in 1996. ... The public domain comprises the body of all creative works and other knowledge—writing, artwork, music, science, inventions, and others—in which no person or organization has any proprietary interest. ... An illustration from the 1918 edition Henry Grays Anatomy of the Human Body, commonly known as Grays Anatomy, is an anatomy textbook widely regarded as a classic work on human anatomy. ...

It contains the accessory nerve, which crosses the triangle from the upper 1/3 of sternocleidomastoideus to the lower 2/3 of the trapezius. It is particularly vulnerable to damage at lymph node biopsy, where damage results in an inability to shrug the shoulders or raise the arm above the head (eg, for brushing hair)