Growth of transplants of rat humerus following circumferential division of the periosteum.

The growth of transplants of young rat humeri has been studied following circumferential division of the periosteum at either the proximal or the distal end of the shaft. Periosteal division resulted in bones that were longer than those in which the periosteum was not cut. Following proximal division the experimental bones grew 30% more at both ends than the control bones and 16% more at the proximal end following distal division. There was, however, no difference between the growth of the experimental and control bones at the distal end following distal division of the periosteum. The experimental humeri had less new subperiosteal bone deposited over their diaphyses than the control humeri. These findings support the view that the periosteum is under tension as a result of the activity of the growth plates, and that changes in periosteal tension affect both the growth in length and the deposition of subperiosteal bone.