
Internal Temporomandibular Joint (TMJ) Derangement ...
Diagnosis of disk derangement with reduction requires observation of the jaw when the mouth is opened. When the jaw is opened > 10 mm (measured between the incisal edges of the upper and lower incisors), a click or pop is heard, or a ch is felt, as the disk pops backward over the head of the condyle. The condyle remains on the disk during further opening.