Quantitative analysis of the growth of the hip joint. A radiological study.

Growth of the hip joint is described on the basis of annual radiographs taken of the intact hip joints of 50 boys aged between 5-15 years. The ossification centre of the femoral head grows at a faster rate in breadth than in height. The growth rate in breadth of the bony centrum exceeds also that of the proximal metaphysis and, accordingly, in the case of normal ossification, the radio-anatomical condition of these two parts is characteristic of the age of the individual. The osseous acetabulum also grows at a faster rate in breadth than in depth. In the period studied up until the 15th year the width of the "articular space" gradually decreases. The ossification rate in the age group examined manifests--with slower and faster periods--a gradually declining tendency. The changes revealed by the radiographs have been interpreted from the viewpoint of bone development and an analysis is also given of the spatial conditions of ossification.