A 36-year-old female patient complains about acute pain, clicking in the right temporomandibular joint, burni- ng pain in the region of the right external acoustic meatus. Movements of lower jaw are step-like with short-standing disabling moments and acute pain in the joint. Objectively: the face is symmetric. Occlusion is orthognathic. Palpation of lateral pterygoid muscles is painful on the right. Tomogram shows that bone structure circuits of joints are smooth and slick. What is the most likely diagnosis?