Hip Anatomy in Femoral Acetabular Impingement

The acetabular cartilage complex is interposed between Figure 1: Hip Growth the ilium, ischium, and the pubis. This complex is composed of epiphyseal growth-plate cartilage adjacent to these bones and articular cartilage around the acetabular cavity. Interstitial growth of the triradiate cartilage leads to expansion and enlargement of the acetabulum (25). Development of the acetabulum and femoral head depends on a located femoral head exerting appropriately directed forces on the acetabulum. Thus the normal development of the hip requires a balanced interaction between the growth of the acetabulum and the femoral head (12). The depth and spherical shape of the acetabular development is based on this relationship (12,21,25,37). Soft tissue structures about the hip joint also play an important role in providing joint stability during development of the hip joint. The acetabular labrum contributes from one-fifth to one-half of the socket depth at birth and plays a significant role in the containing the femoral head at birth (37). Disturbances leading to instability result in a spectrum of anatomical variations found in developmental dysplasia of the hip.