Hip bone sacroiliac joint. Each hip bone is connected to the corresponding femur (thigh bone) (forming the primary connection between the bones of the lower limb and the axial skeleton) through the large ball and socket joint of the hip. The hip bone is formed by three parts: ilium, ischium, and pubis. At birth, these three components are separated by hyaline cartilage. They join each other in a Y-shaped portion of cartilage in the acetabulum. By the end of puberty the three regions will have fused together, and by the age of 25 they will have ossified. The two hip bones join
Muscles of the hip the ilium. Together these muscles are commonly referred to as the "iliopsoas". This group consists of the externus and internus obturators, the piriformis, the superior and inferior gemelli, and the quadratus femoris. These six originate at or below the acetabulum of the ilium and insert on or near the greater trochanter of the femur. Additional muscles, such as the rectus femoris and the sartorius, can cause some movement in the hip joint. However these muscles primarily move the knee, and not generally classified as muscles of the hip. The hamstring muscles, which originate mostly from the ischial tuberosity inserting on