Morphological and structural observation of the synovial membranes and their folds relating to the endoscopic findings in the upper cavity of the human temporomandibular joint (author's transl)

Abstract

Since 1974, with Dr. Ohnishi the author has been trying to develop a method for the endoscopic examination of the temporomandibular joint for clinical application.The aim in this paper is to elucidate the histological characteristics of the inner surface, especially the synovial folds, of the temporomandibular joint through the endoscopy. Eleven upper joint cavities of fresh human cadavers were examined endoscopically, macroscopically and histologically.There were many folds on the posterior surface of the disc adjacent to the mandibular fossa. Generally, the synovial membrane was composed of fine collagenic fibers, and some of these fibers were arranged in a wave-like configuration and were visible as small folds protruding from the large folds.Many fine folds were observed on the posteriomesial region of the disc when the jaw opened, but when the jaw closed they accumulated to form large ridge-like folds. At the subsynovial layer of these regions, the fibrous layer which was abundant in elastic fibers extended from the petro-tympanic fissure to the mesial side of the condyle with the opening of the jaw, but became U-shaped with the closing of the jaw.The subsynovial layer in the anterior region of the disc was generally dense, but was observed to be somewhat looser beneath the folds.