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 m ...

which covers parts of the

skull The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, t ...

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

occipital bone The occipital bone () is a 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 lobes of the cer ...

, and the frontal belly, near the

frontal bone The frontal bone is a bone in the human skull. The bone consists of two portions.''Gray's Anatomy'' (1918) These are the vertically oriented squamous part, and the horizontally oriented orbital part, making up the bony part of the forehead, par ...

. 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 peri ...

, and the

occipital artery The occipital artery arises from the external carotid artery opposite the facial artery. Its path is below the posterior belly of digastric to the occipital region. This artery supplies blood to the back of the scalp and sternocleidomastoid muscl ...

. It is innervated by the

facial nerve The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of ta ...

. In humans, the occipitofrontalis helps to create

facial expressions A facial expression is one or more motions or positions of the muscles beneath the skin of the face. According to one set of controversial theories, these movements convey the emotional state of an individual to observers. Facial expressions are a ...

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 The temporal bones are situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebral cortex. The temporal bones are overlaid by the sides of the head known as the temple (anatomy), temples, and house the structur ...

. It inserts into the

epicranial aponeurosis The epicranial aponeurosis (aponeurosis epicranialis, galea aponeurotica) is an aponeurosis (a tough layer of dense fibrous tissue). It covers the upper part of the skull in humans and many other animals. Structure In humans, the epicrani ...

. * the frontal belly, near the

. 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 or ...

of the facial muscles and in the skin above the

eyes Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and con ...

and

nose A nose is a protuberance in vertebrates that houses the nostrils, or nares, which receive and expel air for respiration alongside the mouth. Behind the nose are the olfactory mucosa and the sinuses. Behind the nasal cavity, air next passes th ...

. Some sources consider the occipital and frontal bellies to be two distinct muscles. However,

Terminologia Anatomica ''Terminologia Anatomica'' is the international standard for human anatomical terminology. It is developed by the Federative International Programme on Anatomical Terminology, a program of the International Federation of Associations of Anatomis ...

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 An artery (plural arteries) () is a blood vessel in humans and most animals that takes blood away from the heart to one or more parts of the body (tissues, lungs, brain etc.). Most arteries carry oxygenated blood; the two exceptions are the pu ...

. The frontal belly receives blood from the supraorbital and

supratrochlear The supratrochlear nerve is a branch of the frontal nerve, itself a branch of the ophthalmic nerve (CN V1) from the trigeminal nerve (CN V). It provides sensory innervation to the skin of the forehead and the upper eyelid. Structure The supra ...

arteries, while the occipital belly receives blood from the

Nerve supply

The occipitofrontalis muscle is innervated by the

. Branches of the supraorbital nerve pass through the occipitofrontalis muscle without innervating it to innervate the

lambdoid suture The lambdoid suture (or lambdoidal suture) is a dense, fibrous connective tissue joint on the posterior aspect of the skull that connects the parietal bones with the occipital bone. It is continuous with the occipitomastoid suture. Structure ...

Function

The occipitofrontalis muscle helps to create

. Assisted by the occipital belly, the frontal belly draws the

scalp The scalp is the anatomical area bordered by the human face at the front, and by the neck at the sides and back. Structure The scalp is usually described as having five layers, which can conveniently be remembered as a mnemonic: * S: The s ...

back, which raises the

eyebrow An eyebrow is an area of short hairs above each eye that follows the shape of the lower margin of the brow ridges of some mammals. In humans, eyebrows serve two main functions: first, communication through facial expression, and second, prevent ...

s 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

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 The vertebral column, also known as the backbone or spine, is part of the axial skeleton. The vertebral column is the defining characteristic of a vertebrate in which the notochord (a flexible rod of uniform composition) found in all chordat ...

, 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