The suboccipital triangle is a region of the

neck The neck is the part of the body on many vertebrates that connects the head with the torso. The neck supports the weight of the head and protects the nerves that carry sensory and motor information from the brain down to the rest of the body. In ...

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 capitis 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 semispinalis muscles are a group of three muscles belonging to the transversospinales. These are the semispinalis capitis, the semispinalis cervicis and the semispinalis thoracis. The semispinalis capitis (''complexus'') is situated at the ...

. The floor is formed by the

posterior atlantooccipital membrane The posterior atlantooccipital membrane (posterior atlantooccipital ligament) is a broad but thin membrane. It is connected above to the posterior margin of the foramen magnum and below to the upper border of the posterior arch of the atlas. On e ...

, and the

posterior arch In anatomy, the atlas (C1) is the most superior (first) cervical vertebra of the spine and is located in the neck. It is named for Atlas of Greek mythology because, just as Atlas supported the globe, it supports the entire head. The atlas is t ...

of the

atlas An atlas is a collection of maps; it is typically a bundle of maps of Earth or of a region of Earth. Atlases have traditionally been bound into book form, but today many atlases are in multimedia formats. In addition to presenting geograp ...

. In the deep groove on the upper surface of the posterior arch of the atlas are the

vertebral artery The vertebral arteries are major arteries of the neck. Typically, the vertebral arteries originate from the subclavian arteries. Each vessel courses superiorly along each side of the neck, merging within the skull to form the single, midline ...

and the first cervical or suboccipital nerve. In the past, the vertebral artery was accessed here in order to conduct

angiography Angiography or arteriography is a medical imaging technique used to visualize the inside, or lumen, of blood vessels and organs of the body, with particular interest in the arteries, veins, and the heart chambers. Modern angiography is perfo ...

of the

circle of Willis The circle of Willis (also called Willis' circle, loop of Willis, cerebral arterial circle, and Willis polygon) is a circulatory anastomosis that supplies blood to the brain and surrounding structures in reptiles, birds and mammals, including huma ...

. Presently, formal angiography of the circle of Willis is performed via catheter angiography, with access usually being acquired at the common femoral artery. Alternatively, a computed tomographic angiogram or magnetic resonance angiogram is performed.

Contents of the suboccipital triangle

1) Third part of

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 The trapezius is a large paired trapezoid-shaped surface muscle that extends longitudinally from the occipital bone to the lower thoracic vertebrae of the spine and laterally to the spine of the scapula. It moves the scapula and supports ...

sternocleidomastoid The sternocleidomastoid muscle is one of the largest and most superficial cervical muscles. The primary actions of the muscle are rotation of the head to the opposite side and flexion of the neck. The sternocleidomastoid is innervated by the access ...

and other larger muscles that move the head are refined by the relatively small suboccipital triangle muscles.

Additional images

File:Suboccipital triangle - animation01.gif, Muscles that border the suboccipital triangle. Animation. File:Suboccipital triangle - animation03.gif, Close up. File:Suboccipital triangle.PNG, Deep muscles of the back. Triangle is labeled in turquoise. File:Gray563.png, The vertebral vein.

References

External links

* - "Muscles of the Back - Suboccipital Triangle"
Description at myqth.com
Human head and neck Triangles of the neck {{Portal bar, Anatomy

Contents of the suboccipital triangle

Additional images

See also

References

External links