Diaphyseal remodelling is a pathological process of the proximal phalanges, metatarsals and metacarpals in all established types of clinical leprosy. It is suggested that the changes are the result of sympathetic neuropathy and alteration of peripheral vascular bed dynamics selectively stimulating extracortical osteoclastic and endosteal osteoblastic activity. There is an overall loss of diaphyseal cortical diameter, either in concentric or knife-edge pattern. There is extracortical absorption of bone and coincident endosteal bone deposition. Ultimately, there is diaphyseal pathological fracture, and subsequent resorption of the distal and proximal remnants due to combined continued diaphyseal remodelling and achroosteolysis.