Growth in craniofacial cartilages studied by 3H-thymidine incorporation

Various cartilaginous zones in the craniofacial region were studied using radioactive thymidine incorporation. An increase in the cpm/DNA ratios was found in all zones investigated between the 10th and the 14th day with the exception of the spheno-occipital synchondrosis, corresponding to a period of great weight increase of the animals. Autoradiography of the mandibular condyle revealed no thymidine marking centrally, tending to show that this structure grows purely by surface apposition.