Final answer:
An AP projection of the hip should show the hip joint, including the femoral head, acetabulum, and the surrounding structures such as ischium, ilium, and pubis with identifiable features like the ischial tuberosity and ischial spine, along with supporting ligaments.
Step-by-step explanation:
On an AP projection of the hip, you should see a clear image of the hip joint, which includes the articulation of the head of the femur and the acetabulum of the hip bone. The hip joint is a multiaxial ball-and-socket joint that provides stability and supports the weight of the body during standing and walking. You would also expect to see the surrounding structures such as the ilium, ischium, and pubis, the three regions of the adult hip bone, with specific details like the ischial tuberosity, ischial spine, and the sciatic notches being visible.
Important ligaments such as the iliofemoral, pubofemoral, and ischiofemoral that support the hip in a standing position should also be observable, but may not always be clearly defined in an X-ray image.