Masticatory muscle response to neuromuscular diseases and specific pathologies

The masticatory muscles are a complex bilateral set of four muscles (masseter, temporalis, medial, and lateral pterygoid muscles) that control movement of the temporomandibular joint, between the maxillae and the only moveable bone in the human skull, the mandible. These muscles are capable of fine-tuned gradients of force and movement, as they are required for production of large forces often needed in crushing of hard food items, and finer movements needed for chewing and human speech production. As with other craniofacial muscles, the masticatory muscles have unique phenotypes distinct from limb muscle due to their specialized function and unique developmental origin. Their characteristics include small myofiber cross-sectional area, fiber-type specific grouping (Eriksson and Thornell 1983), and a wide range of myosin that allow for a spectrum of force and contraction speeds (Stål et al. 1994; Korfage et al. 2000).