Frontalis muscle

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Frontalis

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Latin	venter frontalis musculi occipitofrontalis
Gray's	subject #105 379
Origin:	galea aponeurosis
Insertion:	Mastoid process
Artery:	ophthalmic artery
Nerve:	facial nerve
Action:	wrinkles brow
Dorlands/Elsevier	m_22/12549942

The Frontalis 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 has no bony attachments.

Its medial fibers are continuous with those of the Procerus; its immediate fibers blend with the Corrugator and Orbicularis oculi; and its lateral fibers are also blended with the latter muscle over the zygomatic process of the frontal bone.

From these attachments the fibers are directed upward, and join the galea aponeurotica below the coronal suture.

The medial margins of the Frontales are joined together for some distance above the root of the nose; but between the Occipitales there is a considerable, though variable, interval, occupied by the galea aponeurotica.

It is considered by some sources not to be a muscle of its own, but to be a part of the occipitofrontalis muscle.

[edit] Clinical significance

On neurological examination the frontalis muscle is helpful in determining whether a facial nerve abnormality is an upper or lower motor neurone lesion.

In an upper motor neurone facial nerve abnormality, the frontalis is usually spared, so the patient is able to raise his or her eyebrows normally.

In a lower motor neurone facial nerve abnormality, there will be unilateral weakness of one side of the frontalis muscle.

This is because frontalis has bilateral cortical representation.

[edit] Additional images

Muscles of head and neck

[edit] External links

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.