The structure of the mandibular periosteum in rabbits of different ages has been studied by different histological staining techniques and polarization microscopy. The periosteum consisted of two layers. From the inner, cellular layer the functional state could be determined. A reproducible pattern of resorptive and depository areas was found on the bony surface. In the outer, fibrous periosteal layer, collagenous and elastin fibers were running in distinct directions. The masticatory muscles appeared to be attached directly endomysially or indirectly endomysially, via the perimysium or tendinous attachment. From the periosteal structures and the characteristics of muscular fiber attachments to the bone and periosteum, especially in the ramal and condylar areas, it could be concluded that a mechanical influence of the periosteum on condylar growth is very well possible, which will probably vary during life. The masticatory muscles seemed to be only of minor influence in condylar activity.
Age Factors Animals