Only muscle of the four muscles of mastication to occupy a horizontal position. The lateral pterygoids acting together are the prime protracters of the mandible, moving it into a protrusive position. Contractions of both lateral pterygoids along with the suprahyoid and infrahyoid muscles, help depress or open the mandible. The lateral pterygoid can act singly to move the mandible in lateral excursions. Origin of the superior head is the infratemporal crest of the greater wing of the sphenoid.
Inferior head is the lateral pterygoid plate.