The need to perform triple osteotomies of the pelvis passing very close to the articular surface leads to the isolation of bony fragments whose vascularisation may be precarious. To assess the risks of such surgery, we undertook an anatomic study of the vascularisation of the acetabulum in the fetus. 53 specimens were injected to study the vessels to the acetabulum and their distribution within the osteocartilaginous specimen. The acetabular a., a branch of the obturator a., gives a central pedicle distributed to the acetabular fossa, the triradiate cartilage and ending in the three primary bony components. The superior gluteal, inferior gluteal, internal pudendal and obturator aa. form a periacetabular vascular circle. The abundant vascularity of the acetabulum makes massive necrosis improbable in the child. However, there is a zone of precarious anastomosis at the anterior portion of the acetabulum.