Occipitofrontalis muscle

The occipitofrontalis muscle, also known as the epicranius, is a muscle of the human skull that covers parts of the skull's surface. It consists of two parts or bellies: the occipital belly near the occipital bone and the frontal belly near the frontal bone. These two parts are connected by the epicranial aponeurosis, a tough layer of dense fibrous tissue.

Structure

The occipitofrontalis muscle is composed of two main parts:

• Frontal Belly: This part of the muscle is located at the front of the head. It originates from the epicranial aponeurosis and inserts into the skin of the forehead and the eyebrows.

• Occipital Belly: This part is located at the back of the head. It originates from the occipital bone and the mastoid part of the temporal bone. It inserts into the epicranial aponeurosis.

The two bellies are connected by the epicranial aponeurosis, which allows them to work together to move the scalp.

Function

The primary function of the occipitofrontalis muscle is to move the scalp. The frontal belly is responsible for raising the eyebrows and wrinkling the forehead, which is an important aspect of facial expression. The occipital belly assists in retracting the scalp.

Innervation

The occipitofrontalis muscle is innervated by the facial nerve (cranial nerve VII). Specifically, the frontal belly is innervated by the temporal branch of the facial nerve, while the occipital belly is innervated by the posterior auricular branch.

Blood Supply

The blood supply to the occipitofrontalis muscle is provided by branches of the external carotid artery, including the occipital artery and the superficial temporal artery.

Clinical Significance

The occipitofrontalis muscle plays a crucial role in non-verbal communication through facial expressions. Dysfunction of this muscle, such as in Bell's palsy, can lead to an inability to raise the eyebrows or wrinkle the forehead on the affected side.

Related Pages

• Facial muscles
• Facial nerve
• Epicranial aponeurosis
• Skull