What is the basic normal anatomy of the hip?
The hip is a ball-and-socket joint formed by the femoral head and the acetabulum, providing a large range of multidirectional motion. The acetabulum is tilted anteriorly, allowing a greater degree of flexion than extension. It covers 40% of the femoral head, and its depth is increased by the acetabular labrum, a horseshoe-shaped fibrocartilagenous structure covering the rim of the posterior, superior, and anterior acetabulum. The proximal femur consists of the head, neck, and lesser and greater trochanters. The mostly spherical femoral head, except for the fovea (an indentation in the medial femoral head), is covered by the articular cartilage, which extends over the epiphyseal part of the head to the head-neck junction. The greater femoral trochanter serves as the site of attachment for the hip abductors and lateral rotators (gluteus medius and minimus, obturator internus and externus, and piriformis muscles). The iliopsoas tendon inserts on the lesser trochanter.