[Comparative morphological studies of the structure of the articular disk of the temporomandibular joint]

Articular disks (DA) of mandibular articulations of several types of animals of different ages and both sexes (herbivora, carnivora, rodents and omnivora) were studied. Comparative macroscopy emphasized similarities with the DA of humans and other omnivora, as well as some peculiarities. DA is ellyptical in herbivora; its upper surface is divided into two facets by a transversal crest. DA is pinkish and square in carnivora; its posterior part is lacking. DA is half-moonish and white-nacreous in rodents; its upper surface presents a longitudinal crest. Microscopy evidenced some differences: the collagen fibrils are dominating in herbivora, while in carnivora the elastic ones. The rodents present rare elastic fibers; these animals and the ruminants show capillaries in the central part of the DA, while in other animals these are absent. Cells are mainly located in the upper superficial layers of DA. Relationships between form, histological structure and functions, mainly regarding the mastication types, are discussed.