https://orthoinfo.aaos.org/en/treatment/hip-resurfacing/
Healthy Hip Joint
The anterior view of a healthy hip. You can see the right side of the pelvis as well as how at the proximal end (closest to the body) of the femur there is a femoral neck with the femoral head at the very end. The femoral head is the ‘ball’ part of the hip joint, and the acetabulum is the ‘socket’ component complimenting one another as a function ‘ball and socket’ joint.