Bone density and ash studies in avian osteopetrosis.

Bone density and ash were measured in diaphyses of osteopetrotic and normal chicken tibiotarsi. In lesions of less than one year's duration, osteopetrotic bone was less dense than disease-free bone. The new osteopetrotic bone yielded approximately the same ash content per unit bone dry weight, as did disease-free bone of comparable age, but there was consistently less ash per unit bone wet volume in the diseased bones. This indicates that, in its early stages, osteopetrosis is characterized by spongy bone that lacks dense mineral deposition.