In his work on orthroplastics of the temperomandibular articulation, Murphy classified the ankylosis which occurs in and about the temporomandibular articulation under four heads: (1) intra-articular bony ankylosis; (2) intra-articular fibrous ankylosis; (3) subzygomatic cicatricial fixations, and (4) intraalveolar buccal fixations. The only part of this subject which I shall consider at this time is the first division of Murphy's classification, intra-articular bony ankylosis, or true ankylosis. While this affection is not rare, there have been comparatively few actual cases with results reported, and the work done along this line, and reported in medical or dental literature, is by no means extensive. For the purpose of clearer statement, let us review briefly the temporomandibular joint. Owing to the character and location of this joint, it is particularly susceptible to traumatism and infection. When the complex mechanism and environment of this joint is considered, it can readily be seen that an