Prenatal development of the human pelvis and acetabulum.

The prenatal development of the human pelvic bone and acetabulum has been studied by means of classical histology and microradiography. The embryonic phase leads to a fully developed hip within 8 weeks of gestation. The fetal period is a growth phase, including the following main features: endochondral ossification of the ilium from the ninth week, asymmetrical development of the iliac shaft from the fifteenth week, "chondroid-like" tissue formation above the acetabulum from the twenty-sixth week and haversian bone remodelling from the twenty-eighth week. The fetal development of the pelvis and acetabulum seems to be highly related to mechanical stimuli, the most important being the gluteal muscular activity and the simultaneous pressure of the femoral head.