The occipitofrontalis muscle (epicranius muscle) is a

muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...

which covers parts of the skull. It consists of two parts or bellies: the occipital belly, near the

occipital bone The occipital bone () is a neurocranium, cranial dermal bone and the main bone of the occiput (back and lower part of the skull). It is trapezoidal in shape and curved on itself like a shallow dish. The occipital bone overlies the occipital lobe ...

, and the frontal belly, near the frontal bone. It is supplied by the supraorbital artery, the

supratrochlear artery The supratrochlear artery (or frontal artery) is one of the terminal branches of the ophthalmic artery. It arises within the orbit. It exits the orbit alongside the supratrochlear nerve. It contributes arterial supply to the skin, muscles and peric ...

, and the occipital artery. It is innervated by the facial nerve. In humans, the occipitofrontalis helps to create facial expressions.

Structure

The occipitofrontalis muscle consists of two parts or bellies: * the occipital belly, near the

. It originates on the lateral two-thirds of the highest nuchal line, and on the mastoid process of the temporal bone. It inserts into the epicranial aponeurosis. * the frontal belly, near the frontal bone. It originates from an intermediate tendon that connects to the occipital belly. It inserts in the

fascia A fascia (; plural fasciae or fascias; adjective fascial; from Latin: "band") is a band or sheet of connective tissue, primarily collagen, beneath the skin that attaches to, stabilizes, encloses, and separates muscles and other internal organs. ...

of the facial muscles and in the skin above the eyes and nose. Some sources consider the occipital and frontal bellies to be two distinct muscles. However, Terminologia Anatomica currently classifies it as a single muscle, and also includes the temporoparietalis muscle as part of the epicranius. The occipitofrontalis muscle receives blood from several arteries. The frontal belly receives blood from the

supraorbital Supraorbital refers to the region immediately above the eye sockets, where in humans the eyebrows are located. It denotes several anatomical features, such as: *Supraorbital artery *Supraorbital foramen *Supraorbital gland *Supraorbital nerve *Sup ...

and supratrochlear arteries, while the occipital belly receives blood from the occipital artery.

Nerve supply

The occipitofrontalis muscle is innervated by the facial nerve. Branches of the

supraorbital nerve The supraorbital nerve is one of two branches of the frontal nerve, itself a branch of the ophthalmic nerve. The other branch of the frontal nerve is the supratrochlear nerve. Structure The supraorbital nerve branches from the frontal nerve mid ...

pass through the occipitofrontalis muscle without innervating it to innervate the lambdoid suture.

Function

The occipitofrontalis muscle helps to create facial expressions. Assisted by the occipital belly, the frontal belly draws the scalp back, which raises the eyebrows and wrinkles the

forehead In human anatomy, the forehead is an area of the head bounded by three features, two of the skull and one of the scalp. The top of the forehead is marked by the hairline, the edge of the area where hair on the scalp grows. The bottom of the fore ...

Clinical significance

Damage to the facial nerve can cause atony of the occipitofrontalis muscle.

Other animals

In humans, the occipitofrontalis only serves for facial expressions. In apes, however, the head is not balanced on the vertebral column, and apes therefore need strong muscles that pull back on the skull and prominent

supraorbital ridge The brow ridge, or supraorbital ridge known as superciliary arch in medicine, is a bony ridge located above the eye sockets of all primates. In humans, the eyebrows are located on their lower margin. Structure The brow ridge is a nodule or crest ...

s for the attachment of these muscles.

References

External links

* {{Authority control Muscles of the head and neck