The growth of the first cervical vertebra in the rat

With the help of in vivo marking with alizarin red S, the patterns of growth of the first cervical vertebra are demonstrated. Major parts of the developmental events which take place during growth (differential bone formation on the bone ends facing the synchondroses, closure of the dorsal synchondrosis at 14 days, closure of the ventral synchondroses at 35 to 40 days) may be explained by the influence that a capsular matrix exerts on its protecting and supporting skeletal unit. A demonstrated continued increase of the dorsoventral diameter of the bone is suggested to be an adjustive growth process related to the translative movements of foramen magnum, a topic that has been poorly understood and incompletely investigated.