Dystrophies of the Skeleton

Abstract

Dystrophies of the skeleton can be classified into certain well-defined groups by their characteristic radiographic appearances. (1) Albers-Schönberg's disease, in which the new bone laid down is dense, devoid of normal cancellous structure and shows a tendency to relative fragility. (2) Osteogenesis imperfecta characterised in the infant by marked osteoporosis, defective moulding and fragility, and later by defective development, bending and deformity of the bones subjected to weight or strain. (3) Achondroplasia, with its characteristic dwarfing and prominent tuberosities of the long bones and premature fusion of the base of the skull. (4) Chondro-osteo-dystrophy showing defects in fœtal and infantile ossification resulting in pressure deformities most noticeable in the spine and joints of the lower extremities. (5) Multiple exostoses, a dystrophy having very marked hereditary tendencies and showing multiple bony protuberances growing from near the ends of the diaphyses. (6) Multiple chondromata, though generally associated with bilateral bony defects, presenting a unilateral dwarfing of one or more limbs. Certain other rare skeletal dystrophies have been described which do not conform to the above, but which may also be classified when further examples have been collected. Though it is not always possible to obtain evidence of hereditary taint, the evidence is so conclusive in some types that the possibility of this taint existing as a recessive factor cannot be ignored. None of these dystrophies have been found to possess characteristic histological findings or specific biochemical reactions, and so far they have not been related to endocrine dysfunction or checked in development, except in the case of multiple exostoses and chondromata which may be treated by local surgical excision. It is in differential diagnosis that a knowledge of these dystrophies is of most importance.