Posterolateral view of the suboccipital region.  The suboccipital region has been dissected bilaterally to demonstrate the muscles that form the suboccipital triangle: obliquus capitis inferior, obliquus capitis superior, and rectus capitis posterior major.  A fourth muscle, rectus capitis posterior minor, is located medial to the triangle on each side.  On the left side the vertebral artery is visible within the suboccipital triangle.  The C2 spinal nerve can be seen emerging below the obliquus capitis inferior muscle between C1 and C2 vertebrae.  Also on the left side the occipital artery is shown emerging laterally and crossing the suboccipital region to supply the posterior scalp.