THE FUNCTION OF DISCOMUSCULAR RELATIONSHIPS IN THE HUMAN TEMPOROMANDIBULAR-JOINT

The aim of this morphological study was to investigate whether muscle tissue attaches directly to the discus articularis of the human tempor omandibular joint (TMJ) and to indicate the probable significance of s uch attachments for the function of this articulation. The macroscopic and microscopic findings were derived from tired and unfixed human TM J of varying ages and genders, whereby the functional maturity of the masticatory apparatus was taken into consideration. To date, the resul ts of this study show that aside from fibers originating from the supe rior venter of the m. pterygoideus lateralis, additional muscle or con nective tissue fibers from the perimysium of the m. masseter insert to varying extent in the disc. The same is true for the m. temporalis, w hich is also directly connected to the disc via muscular or fibrous el ements, or indirectly via fibers from the m. masseter. The insertion o f the m. pterygoideus lateralis is always in the medial portion of the discus articularis and those of the mm. temporalis and masseter, resp ectively, in the middle and lateral portions of the disc. It is highly probable that a direct force transfer through the mm. temporalis and masseter to the articular disc takes place, and that these muscles con tribute to the movement of the disc during jaw movement, whereas the s ize and form of the muscle insertions are subject to a great deal of i ndividual variation. Differences were observed between immature and ma ture TMJ as well as between partly and fully toothed masticatory appar atuses.