サラブレッドの化骨に関するX線学的研究

2. 第三中手骨遠位端, 基節骨近位端および橈骨遠位端の骨端線の閉鎖融合過程ならびに骨成熟評価法について

抄録

Ossification changes were examined radiographically in the fetlock (the distal epiphyseal line of the 3rd metacarpal bone and the proximal epiphyseal line of the proximal phalanx) and the distal epiphyseal line of the radius in 804 Thoroughbreds 0 to 26 months of age, and in the olecranon tuberosity and the tuber calcaneus in 67 Thoroughbreds 25 and 26 months of age (The explanation for counting 0 to 24 months is the same as described by Yoshida et al. in 1981). A medthod was devised to assess the stage of development by recording information on the epiphyseal line and epiphysis. Standard radiographs were corrected and added to the skeletal score. The results obtained are as follows: (1) At the age of 0 to 8 months the fetlock varied in deformity. The closure of the epiphyseal line in the fetlock was completed in 8% at 8 months of age, in 70% at 12 months, and in 100% at 14 months. (2) At the age of 6 to 16 months no deformity was defined in the distal epiphyseal line of the radius. The closure of this line at this site was completed in 2.5% at 23 months of age, in 25.9% at 24 months, in 65.1% at 25 months, and in 70.8% at 26 months. (3) The process of bone maturation could be divided into 8 stages for the fetlock and into 7 stages for the distal epiphyseal line of the radius. (4) The compact substance of the proximal phalanx increased statistically in width at 7 to 9 months of age. (5) The stage of development was replaced by the skeletal score. It was evaluated on the basis of this score. (6) The skeletal score curve increased statistically at 0 to 8 months of age. (7) The skeletal score was higher in the female at many times, especially at 14 to 26 months, than in the male.