Occipitalis muscle

At a glance

English

Occipitalis muscle

Latin (TA2)

Musculus occipitalis

System

Muscle

Region

Head

Side

Paired, left and right

About the occipitalis muscle

The occipitalis, or occipital belly, is the posterior part of the occipitofrontalis, the muscle that moves the scalp. Some accounts treat it as a muscle in its own right, but current terminology classes it together with the frontalis as two bellies of one muscle, linked by the broad epicranial aponeurosis that covers the vault of the skull. It is a thin, quadrilateral sheet lying under the skin at the back of the head, above the hairline.

Its fibres arise by short tendinous strands from the lateral part of the occipital bone's superior nuchal line and from the adjoining mastoid part of the temporal bone. They pass upwards and end in the back edge of the epicranial aponeurosis. The two occipital bellies are smaller than the frontal ones and stay widely separated across the midline, with the aponeurosis filling the gap between them and attaching to the external occipital protuberance and the highest nuchal line.

On its own the occipitalis pulls the scalp backwards. Its more important role is to anchor the aponeurosis from behind, so that when the frontalis contracts the eyebrows rise and the forehead wrinkles rather than the scalp sliding forwards. By alternating the two bellies, some people can move the whole scalp back and forth.

It is supplied by the posterior auricular branch of the facial nerve, which reaches it behind the ear, and its blood comes mainly from the occipital artery, with help from the posterior auricular artery. Tension in this muscle and the scalp is often blamed in tension-type headache, and the greater occipital nerve, which pierces the tissues nearby to supply the skin of the back of the scalp, is a common site for nerve blocks in occipital headache. Wounds of the scalp that cut through the aponeurosis gape widely, because the two bellies pull the edges apart.

Attachments, action and supply

Origin

Lateral part of the occipital bone's superior nuchal line and the mastoid part of the temporal bone.

Insertion

Back edge of the epicranial aponeurosis.

Action

Draws the scalp backwards and anchors the aponeurosis so the frontalis can raise the eyebrows.

Nerve supply

Posterior auricular branch of the facial nerve (cranial nerve VII).

Blood supply

Occipital artery, with the posterior auricular artery.