ON CERTAIN ALTERATIONS OF FORM IN THE HEAD AND NECK OF THE THIGH BONE. [Illustration] When treating of atrophy of the articular cartilages, it was observed that, in the latter stages of the disease, the subjacent bone was liable to become denuded, and its articular extremity more or less deformed. Now one of the most interesting of these changes occurs in the head of the thigh bone, which becomes polished on its surface, flattened and expanded, with a corresponding alteration in the acetabulum. In other cases the head of the thigh bone is somewhat elongated, and the acetabulum becomes deepened in proportion, by a deposition of new bone around its margin, as shown in the preceding page, frequently to such an extent as to render the removal of the head of the bone, even after the removal of all the soft parts by maceration, almost impossible without fracture of the edge of the socket. The head of the bone may also become still further misshapen, and anchylosis result; while in some instances the new bony matter presents in the form of nodosities, sometimes projecting towards the cavity of the articulation. This cut represents a section of the upper end of the femur of a labouring man, aged 49, who had fallen on the trochanter ten years before death, and became gradually lame in consequence, with shortening of the limb and anchylosis of the joint, although he had never been confined more than a day or two on account of the injury. [Illustration] [Illustration] But there is another affection in which the femur may be shortened in a comparatively brief space of time from absorption of the intra-capsular portion of its neck, generally succeeding to a fall on the trochanter, and sometimes occurring in young and middle-aged subjects. In treating of fractures of the cervix femoris, it will be observed that retraction of the limb is occasionally delayed for a while: hence the importance of an accurate knowledge of those cases in which shortening of the neck of the thigh bone may succeed to an injury short of fracture. The deficiency of accurate anatomical details concerning such cases led to a doubt as to their existence; but this question has been completely put at rest since the history and dissection of two unequivocal examples by Mr. Gulliver; and the annexed cut represents the changes of form in the head of the bone, the shortening of the neck and comparative length of the femora, in a young man from whom these bones were obtained, and who walked about as many others have done, during the progress of the disease.