A Finite Element Model to Study the Control of Disc Movement Within the Temporomandibular Joint

A two-dimensional non-linear finite element model allowing large displacements and arbitrary contact of surfaces was developed to study the dynamics the human temporomandibular joint (TMJ). The model consists primarily of three deformable bodies: the glenoid fossa portion of the temporal bone, the mandibular condyle, and the articular disc in between. The motion of normal opening was approximated by making a series of small steps with a complete static analysis being done for each one. The kinematics of the in vivo joint can be simulated by rapidly displaying the deformed geometry of one step right after another. The motion of the model was designed to mimic in vivo condylar motion as determined by cineradiographic studies done on two normal subjects. It was found that the disc follows along with the moving condyle imitating in vivo motion even when there are no attachments to the disc. This finding supports the contention that movement of the disc is not controlled by the lateral pterygoid muscle.