Growth in the basicranial synchondroses of adolescent Macaca mulatta

Tritiated thymidine was administered to five Macaca mulatta monkeys ranging in skeletal age from 39 to 48 months. The animals were then serially sacrificed according to the following postinjection schedule: 6 hours, 12 hours, 2, 4, and 7 days. Each animal was given oxytetracycline 370, 103, and 7 days prior to sacrifice. The spheno-occipital and midsphenoidal synchondroses were excised and sectioned midsagittally for histologic preparation and undecalcified "ground" sections. Results from this investigation indicate that from 39 to 48 months of age growth occurs primarily in the spheno-occipital synchrondroses. The greatest mitotic activity occurs within the proliferative zones, while the central zone appears to be relatively inactive. The surface remodeling pattern, which tends to flex the basiocciput relative to the basisphenoid, appears to be compensated for by a supero-inferior growth rate differential within the spheno-occipital cartilage.