[Reconsideration of the bilaminar zone in the retrodiscal connective tissue of the TMJ. 2. Fibrous structure of the retrodiscal connective tissue and relation between those fibers and the disk].

The fibrous structure of the retrodiscal connective tissue was investigated histologically in order to reconfirm what Rees calls the bilaminar zone. Eleven TMJs were taken from the fresh cadavers. The sections, obtained from six materials with condyle protruded, were observed mainly. The Results were as follows: The retrodiscal area was composed of the collagen fibers originating into this area from the petrotympanic fissure, from the conjunctive area of the posterior wall of the fossa with the lateral wall of the articular cavity, and from the conjunctive area of the posterior slope of the auricular tubercle with the lateral wall of the articular cavity. In the superficial layer of the retrodiscal area, these fibers crossed each other, and a few fibers jointed with these fibers from the superficial layer of the disk and from the posterior wall of the articular fossa. The arrangement of these fibers had various directions, however most of fibers tended to run medio-laterally. The fiber bundles containing many elastic fibers ran into the retrodiscal area from the petrotympanic fissure. Although these fibers connected the most medial side of the disk with the medial side of the posterior wall of the articular fossa, they had many branches composing the retrodiscal area as stayed above. The fibers were very wavy, in spite of the protruded position of the disk. So these fibers were not considered to have a role in pulling back the disk in the retruded phase of the mouth closing. New findings as to the retrodiscal connective tissue were obtain in this research. They were different from Ree's description.