Suboccipital Triangle

Boundaries:

Inferior-Obliquus Capitis Inferior

Lateral-Obliquus Capitis Superior

Medial-Rectus Capitis Posterior Major

The posterior atlanto-occipital membrane and the posterior arch of the atlas form the floor of the triangle. The semispinalis capitis muscle is the roof of the triangle. The Suboccipital Triangle contains the vertebral artery and the suboccipital nerve. This is the transition point of the second and third portion of the vertebral artery.

In the suboccipital region the vertebral arteries each have a winding course before ascending and anastomosing with each other to form the basilar artery (vertebrobasilar system). The basilar artery is the main vascular supply to the brainstem, posterior cerebrum, and cerebellum.

The winding course of the vertebral artery is protective. The vertebral artery is seldom violated by neck or head trauma.