A fairly common cause of painful hips in children is the condition variously known as transitory arthritis of the hip joint, transitory coxitis, coxitis serosa seu simplex, acute transient epiphysitis, and transient synovitis. It is now felt that the term transient synovitis most aptly describes the condition, because the pathology seems to lie within the synovial membrane of the hip joint and to be excluded from the other structures within the hip. The malady is of interest, not because it is a disabling condition, but because of the difficulty encountered in differentiating it from more serious diseases of the hip, such as tuberculosis, osteomyelitis, or Legg-Perthes' disease. Literature on the subject is rather scarce, only a few articles being found. Belmonte,1reporting on the condition in 1931, stated, "It is wonderful how the functional disturbance completely disappears in several days, and after ten to twelve days, all complaints depart."