Effect of plaster-cast immobilization on the bone.

Plaster-cast of the right hind limb resulted in immobilization osteoporosis in rats. The alteration was characterized by loss of the bony substance as well as by a partial transformation of lamellar bone to primordial osseous tissue. In the basis of histological and histomorphometric findings, an accelerated osteoclastic activity, an increased osteocytic osteolysis and a decreased ossification are responsible for the observed changes.