Lateral pterygoid muscle

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Lateral pterygoid muscle

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.)

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:	external pterygoid nerve from the mandibular nerve
Action:	depresses mandible
MeSH	Pterygoid+Muscles
Dorlands/Elsevier	m_22/12550292

The lateral pterygoid (or external pterygoid) is a muscle of mastication with two heads.

1 Origin and insertion
2 Innervation
3 Function
4 Additional images
5 External links

[edit] Origin and insertion

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.

[edit] Innervation

The mandibular branch of the fifth cranial nerve, the trigeminal nerve, innervates the lateral pterygoid muscle.

[edit] Function

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.