[Histological studies on growth and function of condylar process in rat mandible].
The purpose of this study was to investigate the growth direction and the function of the mandibular condyle with the observations of the bone structure. Seven week-old rats were used as materials and the condylar processes were studied by macroscopic, light microscopic and electron microscopic observations. The results were as follows: 1. Many types of bone of different degree of calcification and differentiation were observed in the condylar processes. The calcified cartilage and immature bone, which were highly calcified, function as the core of bone trabeculae and compact bone. Each core was surrounded by other types of bone, and then, it seemed that some of these types of bone gave the characteristics of stiffness and flexibility to the bone trabeculae and compact bone. 2. The bone trabeculae indicated the rational arrangements in the condylar process, and as a result, the pressure from the mandibular fossa was transmitted to the compact bone efficiently in the masticatory movement. 3. The condylar processes in these week-old rats were growing only backward. 4. It seemed that the function as the articular head was enhanced mainly after seven week-old though the condylar process grew while it was functioning until this stage.
Ohsako
M
M
Department of Sports and Wellness, School of Literature, Toyo University.
D000818:Animals; D002113:Calcification, Physiologic; D008297:Male; D008335:Mandibular Condyle / Q000033:anatomy & histology* / Q000254:growth & development / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar