Digastric muscle: Difference between revisions

Jump to navigation Jump to search
No edit summary
(No difference)

Revision as of 16:06, 4 June 2009

Template:Infobox Muscle

WikiDoc Resources for Digastric muscle

Articles

Most recent articles on Digastric muscle

Most cited articles on Digastric muscle

Review articles on Digastric muscle

Articles on Digastric muscle in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Digastric muscle

Images of Digastric muscle

Photos of Digastric muscle

Podcasts & MP3s on Digastric muscle

Videos on Digastric muscle

Evidence Based Medicine

Cochrane Collaboration on Digastric muscle

Bandolier on Digastric muscle

TRIP on Digastric muscle

Clinical Trials

Ongoing Trials on Digastric muscle at Clinical Trials.gov

Trial results on Digastric muscle

Clinical Trials on Digastric muscle at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Digastric muscle

NICE Guidance on Digastric muscle

NHS PRODIGY Guidance

FDA on Digastric muscle

CDC on Digastric muscle

Books

Books on Digastric muscle

News

Digastric muscle in the news

Be alerted to news on Digastric muscle

News trends on Digastric muscle

Commentary

Blogs on Digastric muscle

Definitions

Definitions of Digastric muscle

Patient Resources / Community

Patient resources on Digastric muscle

Discussion groups on Digastric muscle

Patient Handouts on Digastric muscle

Directions to Hospitals Treating Digastric muscle

Risk calculators and risk factors for Digastric muscle

Healthcare Provider Resources

Symptoms of Digastric muscle

Causes & Risk Factors for Digastric muscle

Diagnostic studies for Digastric muscle

Treatment of Digastric muscle

Continuing Medical Education (CME)

CME Programs on Digastric muscle

International

Digastric muscle en Espanol

Digastric muscle en Francais

Business

Digastric muscle in the Marketplace

Patents on Digastric muscle

Experimental / Informatics

List of terms related to Digastric muscle

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Please Take Over This Page and Apply to be Editor-In-Chief for this topic: There can be one or more than one Editor-In-Chief. You may also apply to be an Associate Editor-In-Chief of one of the subtopics below. Please mail us [2] to indicate your interest in serving either as an Editor-In-Chief of the entire topic or as an Associate Editor-In-Chief for a subtopic. Please be sure to attach your CV and or biographical sketch.

The digastric muscle (named digastric as it has two bellies) is a small muscle located under the jaw.

It lies below the body of the mandible, and extends, in a curved form, from the mastoid process to the symphysis menti. It belongs to the suprahyoid muscles group.

A broad aponeurotic layer is given off from the tendon of the Digastricus on either side, to be attached to the body and greater cornu of the hyoid bone; this is termed the suprahyoid aponeurosis.

Structure

The Digastricus (Digastric muscle) consists of two fleshy bellies united by an intermediate rounded tendon.

The two bellies of the digastric muscle have different embryological origins, and are supplied by different cranial nerves.

Posterior belly

The posterior belly, longer than the anterior, arises on the inferior surface of the skull, from the medial surface of the mastoid process of the temporal bone and a deep groove between the mastoid process and the styloid process called the digastric groove.

The posterior belly is supplied by a branch of the facial nerve.

Anterior belly

The anterior belly arises from a depression on the inner side of the lower border of the mandible, close to the symphysis, and passes downward and backward.

The anterior body supplied by the trigeminal via the mylohyoid nerve.

Intermediate tendon

The two bellies end in an intermediate tendon which perforates the Stylohyoideus muscle, and is held in connection with the side of the body and the greater cornu of the hyoid bone by a fibrous loop, which is sometimes lined by a mucous sheath.

Action

When the digastric muscle contracts, it acts to elevate the hyoid bone.

If the hyoid is being held in place (by the infrahyoid muscles), it will tend to depress the mandible (open the mouth).

Variations

Variations are numerous.

The posterior belly may arise partly or entirely from the styloid process, or be connected by a slip to the middle or inferior constrictor; the anterior belly may be double or extra slips from this belly may pass to the jaw or Mylohyoideus or decussate with a similar slip on opposite side; anterior belly may be absent and posterior belly inserted into the middle of the jaw or hyoid bone.

The tendon may pass in front, more rarely behind the Stylohoideus. The Mentohyoideus muscle passes from the body of hyoid bone to chin.

Triangles

The Digastricus divides the anterior triangle of the neck into three smaller triangles.

  • (1) the submaxillary triangle, bounded above by the lower border of the body of the mandible, and a line drawn from its angle to the Sternocleidomastoideus, below by the posterior belly of the Digastricus and the Stylohyoideus, in front by the anterior belly of the Diagastricus;
  • (2) the carotid triangle, bounded above by the posterior belly of the Digastricus and Stylohyoideus, behind by the Sternocleidomastoideus, below by the Omohyoideus;
  • (3) the suprahyoid or submental triangle, bounded laterally by the anterior belly of the Digastricus, medially by the middle line of the neck from the hyoid bone to the symphysis menti, and inferiorly by the body of the hyoid bone.

Additional images

External links

Template:Gray's Template:Muscles of neck

Template:SIB

de:Musculus digastricus

Template:WH Template:WS