[Histomorphology of secondary cartilage in human fetal mandibles].

The aim of this study was to provide a histomorphological analysis of some secondary cartilages of mandible and temporal bone as observed in human fetuses 18-22 weeks old. The behavior of cartilage was studied in both these regions, which were decalcified, cut at 10 mu, stained with Mallory staining and examined by optical microscopy. In mandible symphysis menti and condylar cartilage were described. The symphysis appeared to be formed by a fibrous cartilagineous structure surrounded by membranous bone. This structure seems be round in the caudal sections and ovoidal in the rostral sections with the major axis perpendicular to the mean sagittal plane. Meanwhile the condyle is formed by secondary cartilage which may be appreciated in this development stage 5 zona. Secondary cartilage was observed also in the temporal bone nearby the primitive glenoid fossa. The development and the importance of these cartilagineous structures are discussed.