ABOUT THE HIP
The hip is one of the largest weight bearing joints in the body. It is a ball-and-socket joint that has two main parts — the femoral head and the acetabulum.
The femoral head is a ball-shaped bone at the top of the femur (thigh bone). The acetabulum is the socket in the pelvis, into which the femoral head fits. To stabilize the joint, ligaments connect the ball to the socket. The joint capsule is lined with a thin membrane called the synovium. The synovium produces a viscous fluid, which lubricates the joint. Small fluid-filled sacs called bursae cushion the joint where there is friction between the tendons, muscles and bones.
Large muscles enable movement of the hip, in addition to providing additional stability. They are the gluteals, abductors, iliopsoas, quadriceps and hamstrings.