Lateral pterygoid muscle
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| 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 | |
| Blood: | ||
| Nerve: | external pterygoid nerve from the mandibular nerve | |
| Action: | ||
| MeSH | A02.633.567.600.700 | |
| Dorlands/Elsevier | m_22/12550292 | |
The lateral pterygoid (or external pterygoid) is a muscle of mastication with two heads.
The upper head originates on the infratemporal surface of the sphenoid bone, and the lower head on the lateral surface of the lateral pterygoid plate.
Both heads insert onto the pterygoid fovea under the condyloid process of the mandible.
It acts to lower the mandible, open the jaw, and help the medial pterygoids in moving the jaw from side to side (mastication).
The mandibular branch of the fifth cranial nerve, the trigeminal nerve, innervates the lateral pterygoid muscle.
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.
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