The frontalis muscle () is a
muscle
Skeletal muscles (commonly referred to as muscles) are Organ (biology), 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 ...
which covers parts of the
forehead 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 ...
. Some sources consider the frontalis muscle to be a distinct muscle. 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 part of the
occipitofrontalis muscle
The occipitofrontalis muscle (epicranius muscle) is a muscle which covers parts of the skull. It consists of two parts or bellies: the occipital belly, near the occipital bone, and the frontal belly, near the frontal bone. It is supplied by th ...
along with the
occipitalis muscle.
In humans, the frontalis muscle only serves for facial expressions.
The frontalis muscle is supplied 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 ...
and 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.
Structure
The frontalis muscle is thin, of a quadrilateral form, and intimately adherent to the
superficial fascia. It is broader than the
occipitalis and its fibers are longer and paler in color. It is located on the front of the head.
The muscle has no bony attachments. Its medial fibers are continuous with those of the
procerus; its intermediate fibers blend with the
corrugator and
orbicularis oculi muscles, thus attached to the skin of the eyebrows; and its lateral fibers are also blended with the latter muscle over the
zygomatic process of 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 ...
.
From these attachments the fibers are directed upward, and join the
galea aponeurotica below the
coronal suture
The coronal suture is a dense, fibrous connective tissue joint that separates the two parietal bones from the frontal bone of the skull.
Structure
The coronal suture lies between the paired parietal bones and the frontal bone of the skull. ...
.
The medial margins of the frontalis muscles are joined together for some distance above the root of the
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 pass ...
; but between the occipitales there is a considerable, though variable, interval, occupied by the
galea aponeurotica.
Function
In humans, the frontalis muscle only serves for facial expressions.
In the eyebrows, its primary function is to lift them (thus opposing the orbital portion of the orbicularis), especially when looking up. It also acts when a view is too distant or dim.
["eye, human."Encyclopædia Britannica. 2008. ]Encyclopædia Britannica 2006 Ultimate Reference Suite DVD
An encyclopedia (American English) or encyclopædia (British English) is a reference work or compendium providing summaries of knowledge either general or special to a particular field or discipline. Encyclopedias are divided into articles ...
2009
The frontalis muscle also serves to wrinkle the forehead.
Additional images
File:Frontalis muscle animation small.gif, Position of frontalis muscle (shown in red)
See also
*
Occipitofrontalis muscle
The occipitofrontalis muscle (epicranius muscle) is a muscle which covers parts of the skull. It consists of two parts or bellies: the occipital belly, near the occipital bone, and the frontal belly, near the frontal bone. It is supplied by th ...
References
External links
PTCentral
{{Authority control
Muscles of the head and neck