Radiographic Studies on Maturation Process of Secondary Ossification Centers in Long Bones of the Japanese White Rabbit

The maturation process of the secondary ossification centers of the extremities was radiographically investigated in the Japanese white rabbit of both sexes aged 1 day to 78 weeks. The ossification centers appeared at 1 day of age in the proximal and distal epiphyses of humerus, the head of femur, the distal epiphysis of femur and the proximal epiphysis of tibia, at 1 week of age in the supraglenoid tubercle of scapula, the proximal and distal epiphyses of radius, the proximal and distal epiphyses of ulna, the greater trochanter of femur, the distal epiphysis of tibia and the distal epiphysis of fibula, and at 2 weeks of age in the proximal epiphysis of fibula. The ossification centers developed rapidly from the time of appearance to 8 weeks of age, and gradually thereafter until 32 weeks of age. By 78 weeks of age, the complete fusion with the diaphysis was observed in the supraglenoid tubercle of scapula, the proximal and distal epiphyses of humerus, the head and distal epiphysis of femur. Incomplete fusion, leaving an epiphyseal line, was found in the proximal and distal epiphyses of radius, ulna, tibia and fibula, respectively.