Appositional growth rate in the spongiosa of unloaded long bones of the dog.

In agreement with the results of previous investigations on the dynamics of diaphyseal osteonic bone in inert skeletal segments, it has been observed that the linear appositional growth rate on the trabecular bone of metaphyses and epiphyses does not significantly change in unloaded bones, in comparison with normally loaded ones. Only during the initial period of unloading, a moderate decrement of the aforesaid parameter seems to take place. These findings are briefly discussed in connection with the role presumably played by mechanical stresses on the processes of bone reconstruction.