Orthodox radiological examination of patients presenting with disorders of the hip, usually on account of pain and limitation of movement, may vary in diagnostic value. As a supplementary study we have employed arthrography. During this procedure we have, since 1970, routinely assessed the capacity of the joint capsule. The normal capacity varies from 20 ml in a large adult male to 14 ml in a small adult female. Significant reduction of this volume has been observed as a secondary complication of certain organic lesions, including four cases of synovial chondromatosis, one case of an intra-articular loose body, and one case of osteoid osteoma of femoral neck. In these secondary cases, the only common feature visible on the plain film was regional osteopenia. In these patients symptoms persisted until adequate surgical measures had been performed. (Descriptive term proposed: secondary capsular constriction of the hip: SCCH). In another group of seven patients, in whom orthodox radiological studies were unrewarding, arthrography was undertaken on account of persistent pain and limitation of movement. Similar reduction in the capacity of the joint was found, but in each case spontaneous resolution of the symptoms took place, without surgical intervention, in periods varying from three to 18 months. This self-limiting syndrome appears to be analogous to that of the "frozen shoulder" and, like the latter, is associated frequently with barbiturism.