INNERVATION OF THE HUMAN LATERAL PTERYGOID MUSCLE

The one- or two-headed arrangement of the lateral pterygoid m. (LPM) w as analysed by studying the motor nerve distribution within the muscul ar tissue. In all subjects, the main innervation of the lateral pteryg oid m. came from the anterior trunk of the mandibular n. by one to thr ee nerves. These nerves divided into five or six vertical branches whi ch ramified into parallel horizontal tiny fibers. Consequently, the la teral pterygoid m. appeared to be divided into oblique sagittal planes and horizontal layers by the nerve branches, reflecting the multipenn ate organisation of the muscle. These layers can be selectively recrui ted during mandibular movements, ensuing a fine medial-lateral control . According to its nerve supply, the LPM has to be considered as a sin gle unit made of independent functional musulo-aponeurotic layers even though its morphologic conformation is in one, two or three heads.