Summary of previous experimental study;
Object of present study.
Relation between changes in bone as a result of lack of use and the cause of the nonuse.
Character of changes in adults.
Character of changes during period of growth.
Effect of nonuse on growth of bone.
Effect of nonuse on regeneration of bone.
Recovery from bone atrophy.
In a previous experimental study of the atrophic changes in bone which follow nonuse of an extremity, it was found that these changes were the same following nerve paralysis, joint injury and mechanic fixation of the extremity. The degree of atrophy of the bone was directly proportional to the degree of nonuse, regardless of the experimental method used to produce nonuse. Mechanical fixation produced as rapidly developing and as marked bone atrophy