Lumbar Spine, Hip & Knee LO4

4. Identify the major joint and associated ligaments in the hip region. Explain what kind of movements occur at the joints and other pertinent information.

The hip joint is a synovial, ball and socket joint, and is the second most mobile joint in the body (2nd to the glenohumeral joint - both ball & socket joints). The joint is formed by the acetabulum of the coxal bone and head of the femur. Medial and lateral rotator muscles of the thigh play an important role in support and structure of the hip joint.

Accessory structures of hip joint:

  • Acetabular labrum is similar in structure to the glenoid labrum of glenohumeral joint, and allows for a better fit between the acetabulum and head of femur. The labrum is incomplete at the level of the acetabular notch.
    • Transverse acetabular ligament completes the lip around the acetabulum at the acetabular notch.
  • Ligaments:
    • Iliofemoral ligament is often considered to be the strongest ligament in the body, and it certainly is for the hip joint. It is expansive (more anteriorly-placed, ilium to femur) and Y-shaped.
      • This ligament plays a strong role in prevention of hyperextension of the hip joint.
    • Pubofemoral ligament is also more anteriorly-place (pubis to femur) and is closely associated with the iliofemoral ligament. This ligament plays a role in prevention of overabduction.
    • Ischiofemoral ligament is posteriorly positioned between the ischium and femur. This is the weakest of the 3 main hip ligaments, but does play a small role in limiting medial rotation and preventing hyperextension.
    • Ligament of head of femur extends from acetabular notch to fovea of femoral head. The primary function of this ligament is not hip joint strengthening but as a conduction site for the artery of the head of femur.
  • Clinical significance:
    • Fracture of neck of femur ("fractured hip"): more common in osteoporotic individuals with ages greater than 60. With a fracture to the neck, disruption of the dominant supply of the head of the femur (medial circumflex femoral a.) is common and may lead to necrosis of the head.