suboccipital triangle

The suboccipital triangles are a paired triangular-shaped space formed by the configuration of three paired muscles in the posterior neck between the occipital bone, C1 and C2.

Gross Anatomy

The suboccipital triangle has an inferomedial pointing apex (pointing towards the nuchal ligament) formed by the rectus capitis posterior major (superomedial border) and the obliuus capitis inferior (inferomedial border) muscles. The base of the triangle is superolaterally formed by the obliquus capitis superior muscle.

The suboccipital triangle 'floor' is deep to the muscular triangle (i.e. anterior), formed by the posterior atlantooccipital membrane and posterior arch of the atlas . The 'roof' is located superficially (i.e. posterior) and is formed by the semispinalis capitis muscle and a dense layer of adipose tissue .

Boundaries

• superomedial border: rectus capitis posterior major
• superolateral border: obliquus capitis superior
• inferomedial border: obliquus capitis inferior

Contents

• dorsal ramus of the first cervical nerve (suboccipital nerve)
• third part of the vertebral artery
• suboccipital venous plexus

Relations

• superior
  • occipital bone
  • foramen magnum
• medial: nuchal ligament
• anterior ('floor')
  • posterior elements of C1 and C2
  • posterior atlanto-occipital membrane
• superficial ('roof')
  • adipose tissue
  • semispinalis capitis muscle
• inferior
  • second cervical dorsal ramus
  • second part of the vertebral artery

Blood Supply

• arterial: branches of the vertebral artery and occipital artery, deep descending branches supply the sub-occipital muscles
• venous: via the sub-occipital venous plexus

Innervation

The muscles of the sub-occipital triangle are innervated by the suboccipital nerve (dorsal ramus of C1) .