Growth potential of the rat clavicle

An experiment was performed to determine whether the clavicle, which is capped with secondary cartilage at both ends, is endowed with a tissue-separating quality or is only adaptive to forces exerted by the surrounding structures. The medial end of the clavicle from 10-day-old male rats was transplanted across the interparietal suture into an opening in the adjoining parietal bones corresponding to the outline of the transplant. The transverse dimensions of the neurocranium when measured at 25 and 35 days of age were greater in the animals with transplants than in the untreated controls. Histologic examination showed that although the cartilaginous component of the transplants was reduced, the zonal arrangements was comparable to that in situ. It was concluded that the medial end of the clavicle has a potential for separating skeletal components and that preservation of the basic structure is dependent on mechanical resistance.