{{Short description|Facial muscle helping to create facial expressions}} {{Infobox muscle | Name = Occipitofrontalis | Latin = musculus occipitofrontalis or musculus epicranii venter frontalis | Image = Gray378.png | Caption = | Origin = Two occipital bellies and two frontal bellies. | Insertion = Epicranial aponeurosis | Blood = Frontal belly: supraorbital and supratrochlear arteries <br/>Occipital belly: occipital artery | Nerve = Facial nerve | Action = Raises eyebrows, wrinkles forehead }} 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 the supraorbital artery, the supratrochlear artery, and the occipital artery. It is innervated by the facial nerve. In humans, the occipitofrontalis helps to create facial expressions.
== Structure == {{Main|occipitalis muscle|frontalis muscle}} The occipitofrontalis muscle consists of two parts or bellies:
* the occipital belly, near the occipital bone.<ref name="GrayStudent862">{{cite book|last1=Drake|first1=Richard L.|title=Gray´s Anatomy for Students|last2=Vogl|first2=A. Wayne|last3=Mitchell|first3=Adam W. M.|year=2010|isbn=978-0-443-06952-9|edition=2nd|pages=862}}</ref> It originates on the lateral two-thirds of the highest nuchal line, and on the mastoid process of the temporal bone.<ref name="Stone-26">{{cite book|last=Stone|first=Robert & Judith|url=https://archive.org/details/atlasskeletalmus02ston|title=Atlas of skeletal muscles|publisher=McGraw-Hill|year=2000|isbn=978-0-07-290332-4|page=[https://archive.org/details/atlasskeletalmus02ston/page/n31 26]|url-access=limited}}</ref> It inserts into the epicranial aponeurosis.<ref name="Stone-26" /> * the frontal belly, near the frontal bone.<ref name="GrayStudent862" /> It originates from an intermediate tendon that connects to the occipital belly.<ref name="Stone-26" /> It inserts in the fascia of the facial muscles and in the skin above the eyes and nose.<ref name="Stone-26" />
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 and supratrochlear arteries, while the occipital belly receives blood from the occipital artery.<ref>{{cite web|year=2007|title=Introduction to the Head; Front of Skull and Face/Muscles of the Face|url=http://anatomy.uams.edu/AnatomyHTML/introheadneck.html|access-date=2008-09-24|publisher=University of Arkansas for Medical Sciences (UAMS)|archive-date=2018-10-21|archive-url=https://web.archive.org/web/20181021220943/http://anatomy.uams.edu/anatomyhtml/introheadneck.html|url-status=dead}}</ref>
=== Nerve supply === The occipitofrontalis muscle is innervated by the facial nerve.<ref name="GrayStudent857">{{cite book|last1=Drake|first1=Richard L.|title=Gray´s Anatomy for Students|last2=Vogl|first2=A. Wayne|last3=Mitchell|first3=Adam W. M.|year=2010|isbn=978-0-443-06952-9|edition=2nd|pages=857}}</ref> Branches of the supraorbital nerve pass through the occipitofrontalis muscle without innervating it to innervate the lambdoid suture.<ref>{{Cite book|last1=Barral|first1=Jean-Pierre|title=Manual therapy for the cranial nerves|last2=Croibier|first2=Alain|publisher=Churchill Livingstone|year=2009|isbn=978-0-7020-3736-8|location=Edinburgh|pages=115–128|language=en|chapter=15 - Ophthalmic nerve|doi=10.1016/B978-0-7020-3100-7.50018-5|oclc=460904284}}</ref>
== Function == The occipitofrontalis muscle helps to create facial expressions.<ref name="Saladin-286-287">{{cite book|last=Saladin|first=Kenneth S.|title=Anatomy & Physiology: The Unity of Form and Function|publisher=McGraw-Hill|year=2003|edition=3rd|pages=286–287}}</ref> Assisted by the occipital belly, the frontal belly draws the scalp back, which raises the eyebrows and wrinkles the forehead.<ref name="GrayStudent857" /><ref name="Stone-26" />
== Clinical significance == Damage to the facial nerve can cause atony of the occipitofrontalis muscle.<ref>{{Cite book|last1=McCain|first1=Joseph P.|title=Current Therapy In Oral and Maxillofacial Surgery|last2=Kim|first2=King|publisher=Saunders|year=2012|isbn=978-1-4160-2527-6|location=Philadelphia|pages=31–62|language=en|chapter=6 - Endoscopic Oral and Maxillofacial Surgery|doi=10.1016/B978-1-4160-2527-6.00006-2|oclc=757994410}}</ref>
== Other animals == {{See also|Human skeletal changes due to bipedalism}}In humans, the occipitofrontalis only serves for facial expressions. In other 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 ridges for the attachment of these muscles.<ref name="Saladin-286-287" />
== See also == * Epicranium
== References == {{Reflist}}
== External links == * {{cite journal | author = Bérzin F | title = Occipitofrontalis muscle: functional analysis revealed by electromyography. | journal = Electromyogr Clin Neurophysiol | volume = 29 | issue = 6 | pages = 355–8 | year = 1989 | pmid = 2689156}}
{{Muscles of head}} {{Authority control}}
Category:Muscles of the head and neck