WordNet

a three-sided polygon (同)trigon, trilateral
something approximating the shape of a triangle; "the coastline of Chile and Argentina and Brazil forms two legs of a triangle"
a percussion instrument consisting of a metal bar bent in the shape of an open triangle
any of various triangular drafting instruments used to draw straight lines at specified angles

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三角形 / 三角形の物 / 《米》三角定規 / (楽器の)トライアングル / 三つ組,三人組;(男女の)三角関係

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/05/25 01:56:22」(JST)

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The suboccipital triangle is a region of the neck bounded by the following three muscles of the suboccipital group of muscles:

Rectus capitis posterior major - above and medially
Obliquus capitis superior - above and laterally
Obliquus capitis inferior - below and laterally

(Rectus capitus posterior minor is also in this region but does not form part of the triangle)

It is covered by a layer of dense fibro-fatty tissue, situated beneath the Semispinalis capitis.

The floor is formed by the posterior occipito-atlantal membrane, and the posterior arch of the atlas.

In the deep groove on the upper surface of the posterior arch of the atlas are the vertebral artery and the first cervical or suboccipital nerve.

The vertebral artery is accessed here in order to conduct angiography of the circle of Willis.

Contents of the suboccipital triangle [edit]

1) Third part of vertebral artery
2) Dorsal ramus of nerve C1-suboccipital nerve
3) Suboccipital venous plexus

The purpose of these muscles is to provide fine motor function in movements of the head. The actions of trapezius, sternocleidomastoid and other larger muscles that move the head are refined by the relatively small suboccipital triangle muscles.

Additional images [edit]

The vertebral vein.

External links [edit]

SUNY Labs 01:11-0101 - "Muscles of the Back - Suboccipital Triangle"
Description at myqth.com

This article incorporates text from a public domain edition of Gray's Anatomy.

This anatomy article is a stub. You can help Wikipedia by expanding it.

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English Journal

Anatomical connection between the rectus capitis posterior major and the dura mater.

Scali F, Marsili ES, Pontell ME.SourceSchool of Medicine, St. George's University, Grenada, West Indies. drfrankscali@gmail.com
Spine.Spine (Phila Pa 1976).2011 Dec 1;36(25):E1612-4.
STUDY DESIGN: Anatomic study performed on 13 cadaveric specimens focused on muscles of the suboccipital triangle, specifically, the rectus capitis posterior major (RCPma).OBJECTIVE: To investigate a connection between the RCPma and the cervical dura mater.SUMMARY OF BACKGROUND DATA: In a study of th
PMID 21278628

Bilateral anomaly of rectus capitis posterior muscles in the suboccipital triangle and its clinical implication.

Nayak SR, Swamy R, Krishnamurthy A, Dasgupta H.SourceDepartment of Anatomy, College of Medicine and J.N.M. Hospital, WBUHS, Kalyani-741235, West Bengal, India. ranjanbhatana@gmail.com
La Clinica terapeutica.Clin Ter.2011;162(4):355-6.
Rectus capitis posterior muscles are located in the suboccipital triangle and function in extension and lateral rotation of the head and neck. There are two of these muscles on each side: the rectus capitis posterior major and the rectus capitis posterior minor. In the present case we observed bilat
PMID 21912824

Japanese Journal

DIRECT SURGERY FOR INTRA-AXIAL BRAINSTEM LESIONS

Kyoshima Kazuhiko,Oikawa Susumu,Kobayashi Shigeaki
The KITAKANTO Medical Journal 48(Special1), 23-28, 1998
… Direct surgery for intra-axial lesions of the brainstem was done for 9 cases : seven cases in the pons (2 cavernous angiomas, 3 gliomas, 2 metastatic tumors) and two in the medulla oblongata (one cavernous angioma, one glioma), by suboccipital craniectomy. … Infrafacial approach will required more meticulous procedures than the suprafacial triangle. …
NAID 130000880032