| Medical Dictionary: lateral pterygoid muscle |
A muscle whose inferior head has origin from the pterygoid process, and whose superior head has origin from the sphenoid bone, with insertion into the mandible and the articular disk, with nerve supply from the lateral pterygoid branch of the trigeminal nerve, and whose action brings the jaw forward and opens it.
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| Wikipedia: Lateral pterygoid muscle |
| Lateral pterygoid muscle | |
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| The Pterygoidei; the zygomatic arch and a portion of the ramus of the mandible have been removed. (Labeled as "pterygoideus externus", visible in pink at center.) | |
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| Sagittal section of the articulation of the mandible. (Labeled as "pterygoideus externus", visible in gray at bottom right.) | |
| Latin | m. pterygoideus lateralis, m. pterygoideus externus |
| Gray's | subject #109 386 |
| Origin | Great wing of sphenoid and pterygoid plate |
| Insertion | Condyle of mandible |
| Artery | pterygoid branches of maxillary artery |
| Nerve | lateral pterygoid nerve from the mandibular nerve |
| Actions | depresses mandible, Protrude mandible, side to side movement of mandible |
| MeSH | Pterygoid+Muscles |
The lateral pterygoid (or external pterygoid) is a muscle of mastication with two heads.
Contents |
The upper/superior head originates on the infratemporal surface and infratemporal crest of the greater wing of the sphenoid bone, and the lower/inferior head on the lateral surface of the lateral pterygoid plate.
Inferior head inserts onto the pterygoid fovea under the condylar process of the mandible; upper/superior head inserts onto the articular disc and fibrous capsule of the TMJ.
The mandibular branch of the fifth cranial nerve, the trigeminal nerve, innervates the lateral pterygoid muscle.
It acts to lower the mandible, open the jaw, and help the medial pterygoids in moving the jaw from side to side (mastication).
Unlike the other three muscles of mastication, the lateral pterygoid is the only one that opens the jaw, or depresses the mandible. At the beginning of this action it is assisted by the digastric, mylohyoid and geniohyoid muscles.
 Sphenoid bone. Anterior and inferior surfaces. |
 Mandible. Inner surface. Side view. |
 Plan of branches of internal maxillary artery. |
 Distribution of the maxillary and mandibular nerves, and the submaxillary ganglion. |
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 | Medical Dictionary. The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Read more |
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