Clinically, tuberculous processes in the long bones of children may be divided into two groups according to location: (1) those in the diaphysis and (2) those in the metaphyso-epiphyseal region. In either case, the primary factor is a lodgment of tubercle bacilli in the interior of the bone. Just what type of lesion results depends on the individual reaction of each patient, but for the most part lesions are formed that are characteristic of each region. As the bacilli multiply and grow, typical tuberculous follicles with lymphocytes and epithelioid and giant cells are formed. These coalesce, and at the center caseation begins, with fibrosis at the periphery. If the lesion is at the metaphyso-epiphyseal region, a cystic structure results. Here, in most cases, the caseation is more rapid than the fibrosis, and the process infiltrates the surrounding tissue, with subsequent epiphyseal destruction and involvement of the joint. Tuberculosis of the