The temporomandibular joint (TM joint) is a synovial joint with two condylar surfaces and an intra-articular cartilaginous disc. Its development has two origins. Its physiology is complex and intimately related to dental occlusion, which is why we talk about the temporomandibular and dental joint. Recent neurophysiological data allow a better approach to TM joint dysfunction. The lateral pterygoid muscle plays decisive role in the pathogenesis of TM joint dysfunction.