Obliquus capitis superior

The obliquus capitis superior (Latin: musculus obliquus capitis superior) is a small paired triangular muscle of the neck that stretches between the occipital bone of the skull and the first cervical vertebra. It is located in the posterior compartment of the neck. Therefore, the obliquus capitis inferior is one of the posterior neck muscles. It is located in the deepest layer of the group. As the obliquus capitis superior is situated below the occipital bone, it is classified as the suboccipital muscle. It acts at two joints - the atlanto-occipital and atlanto-axial joints.

Origin

The obliquus capitis superior muscle originates from the transverse process of the atlas (C1).

Insertion

The fibers of the obliquus capitis superior insert on the lateral aspect of the inferior nuchal line located on the external surface of the occipital bone.

Action

By bilateral contractions, the obliquus capitis superior muscle extends the head at the atlanto-occipital joint. By unilateral contractions, it provides head lateral flexion to the ipsilateral side at the atlanto-axial joint.

Innervation

The obliquus capitis superior is innervated by the suboccipital nerve - the posterior ramus of the 1st cervical spinal nerve (C1).

Blood supply

The obliquus capitis superior muscle receives arterial blood supply from the branches of the vertebral and occipital arteries.