[Articular disk dislocation in the human TMJ]

A three-dimensional model of articular disk dislocations has been developed. Histological examination of 35 temporomandibular joints in near sagittal section reveals sometimes extreme anterior displacement in about 50% and slight posterior displacement of the disk in 6% of the specimens. In the frontal plane medial dislocation prevails in more than 70% of the 32 specimens evaluated, whereas there is only one lateral dislocation. Within the predominantly medio-anterior direction of dislocation there are, however, variations. Excentric forces relative to the center of gravity of the disk always result in dislocations accompanied by rotation in the anterior or posterior part. Where the resulting forces apply on the center of gravity there is a translation in a medio-anterior direction.