A collection of medical and dental conditions affecting the temporomandibular joint (TMJ) and/or muscles of mastication and other contiguous tissue components. Includes myofascial pain‐dysfunction syndrome (MPD), meniscal displacement with or without reduction (internal derangement), degenerative joint disease (osteoarthritis), rheumatoid arthritis, and other disorders of systemic origin, facial growth disharmonies, traumatic injuries, and neoplasms.