Sub-Occipital Triangle
This anatomical region is bounded by rectus capitis posterior major and the superior and inferior oblique muscles.  

In the roof runs the posterior ramus of the C2 nerve root, called the ‘greater occipital nerve’.  This nerve runs under the lower edge of the inferior oblique, then along the roof of the triangle to supply the skin at the posterior scalp.  The greater occipital nerve is easily damaged in operations in this area.

The floor of the triangle contains the posterior arch of C1, the vertebral artery and the posterior ramus of C1.

The muscles in the suboccipital region, together with the small anterior and lateral muscles, are relatively small and weak, but play a large role in the fine control of head movement.  They essentially act as a ‘gyroscope’, being able to perform the finest of head movements.