Occipitofrontalis muscle

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Occipitofrontalis
Gray378.png
Latin Musculus occipitofrontalis
Gray's p.378
Origin Two occipital bellies and two frontal bellies.
Insertion Galea aponeurotica
Artery Frontal belly: supraorbital and supratrochlear arteries
Occipital belly: Occipital artery
Nerve Facial nerve
Actions Raises eyebrows, wrinkles forehead
Anatomical terms of 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.[1] In humans, the occipitofrontalis only serves for facial expressions.[2]

Some sources consider the occipital and frontal belly 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.[3] The occipitofrontalis muscle is innervated by the facial nerve.[4]

Course[edit]

The occipital belly originates on the lateral two-thirds of the superior nuchal line of the occipital bone, and on the mastoid process of the temporal bone. Inserted into the galea aponeurotica, or epicranial aponeurosis, the occipital belly communicates with the frontal belly by an intermediate tendon. From the aponeurosis, the frontal belly is inserted in the fascia of the facial muscles and in the skin above the eyes and nose.[5]

Action[edit]

Assisted by the occipital belly, the frontal belly draws the scalp back which raises the eyebrows and wrinkles the forehead.[4][5]

Evolution[edit]

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 ridges for the attachment of these muscles.[2]

See also[edit]

References[edit]

  1. ^ Drake, Richard L.; Vogl, A. Wayne; Mitchell, Adam W. M. (2010). Gray´s Anatomy for Students (2nd ed.). p. 862. ISBN 978-0-443-06952-9. 
  2. ^ a b Saladin, Kenneth S. (2003). Anatomy & Physiology: The Unity of Form and Function (3rd ed.). McGraw-Hill. pp. 286–287. 
  3. ^ "Introduction to the Head; Front of Skull and Face/Muscles of the Face". University of Arkansas for Medical Sciences (UAMS). 2007. Retrieved 2008-09-24. 
  4. ^ a b Drake, Richard L.; Vogl, A. Wayne; Mitchell, Adam W. M. (2010). Gray´s Anatomy for Students (2nd ed.). p. 857. ISBN 978-0-443-06952-9. 
  5. ^ a b Stone, Robert & Judith (2000). Atlas of skeletal muscles. McGraw-Hill. p. 26. ISBN 978-0-07-290332-4. 

External links[edit]

  • -1341783984 at GPnotebook
  • Bérzin F (1989). "Occipitofrontalis muscle: functional analysis revealed by electromyography.". Electromyogr Clin Neurophysiol 29 (6): 355–8. PMID 2689156.