Nerve entrapment in the lateral pterygoid muscle.

The posterior trunk of the mandibular division of the trigeminal nerve normally descends deep to the lateral pterygoid muscle. In three of 52 dissections the three main branches of the posterior trunk (lingual, inferior alveolar, and auriculotemporal nerves) were observed to pass through the medial fibers of the lower belly of the lateral pterygoid muscle. The mylohyoid and anterior deep temporal nerves also were observed to pass through the lateral pterygoid muscle in other specimens. These nerve entrapments in the infratemporal fossa provide new information concerning the anatomic and clinical relationships between the mandibular nerve and the lateral pterygoid muscle. These findings support the hypothesis that a spastic condition of the lateral pterygoid muscle may be causally related to compression of an entrapped nerve that lead to numbness, pain, or both in the respective areas of nerve distribution.