The occipitofrontalis muscle (epicranius muscle) is a muscle 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, th ...

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

. It is supplied by the

supraorbital artery The supraorbital artery is a branch of the ophthalmic artery. It passes anteriorly within the orbit to exit the orbit through the supraorbital foramen or notch alongside the supraorbital nerve, splitting into two terminal branches which go on to f ...

, the supratrochlear artery, 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 musc ...

. 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 taste ...

. 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 ...

Structure

The occipitofrontalis muscle consists of two parts or bellies: * the occipital belly, near the occipital bone. It originates on the lateral two-thirds of the

highest nuchal line The nuchal lines are four curved lines on the external surface of the occipital bone: * The upper, often faintly marked, is named the highest nuchal line, but is sometimes referred to as the Mempin line or linea suprema, and it attaches to the ep ...

, and on the

mastoid process The mastoid part of the temporal bone is the posterior (back) part of the temporal bone, one of the bones of the skull. Its rough surface gives attachment to various muscles (via tendons) and it has openings for blood vessels. From its borders, ...

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 temples, and house the structures of the ears. ...

. 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 epicranial ...

. * the frontal belly, near the

. It originates from an intermediate tendon that connects to the occipital belly. It inserts in the fascia of the

facial muscles The facial muscles are a group of striated skeletal muscles supplied by the facial nerve (cranial nerve VII) that, among other things, control facial expression. These muscles are also called mimetic muscles. They are only found in mammals, al ...

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 ...

. 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 Anatomi ...

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 supr ...

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 T ...

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 ski ...

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, preven ...

s and wrinkles the forehead.

Clinical significance

Damage to the

can cause

atony This glossary of medical terms is a list of definitions about medicine, its sub-disciplines, and related fields. A * Aarskog–Scott syndrome – (AAS) A rare, inherited (X-linked) disease characterized by short stature, facial abnormalities ...

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 chordate ...

, and apes therefore need strong muscles that pull back on the skull and prominent supraorbital ridges for the attachment of these muscles.

References

External links

* {{Authority control Muscles of the head and neck