Hip Anatomy & Assessment

The Hip Joint

The hip is a ball-and-socket joint formed by the rounded head of the femur (thighbone) fitting into the cup-shaped acetabulum of the pelvis. This configuration provides a wide range of motion while bearing the full weight of the upper body during standing, walking, and physical activity.

The joint surfaces are covered by articular cartilage — a smooth, resilient tissue that absorbs shock and enables frictionless movement. Encircling the rim of the acetabulum is the labrum, a ring of fibrocartilage that deepens the socket, improves stability, and acts as a seal to maintain joint fluid pressure. Surrounding the joint is a fibrous capsule reinforced by strong ligaments, and powerful muscles including the gluteals, hip flexors, and external rotators control and stabilise movement.

Common Causes of Hip Pain

Hip pain can arise from the joint itself or from structures outside it. Identifying the source accurately is essential before any treatment is considered.

• Osteoarthritis — gradual degeneration of articular cartilage, the most common cause of hip pain in adults over 50
• Femoroacetabular impingement (FAI) — abnormal bony contact between the femoral head and acetabular rim, causing pain in younger, active individuals
• Labral tears — often associated with FAI or hip dysplasia, causing groin pain and mechanical symptoms
• Greater trochanteric pain syndrome — pain over the outer hip from gluteal tendinopathy or bursitis
• Avascular necrosis — loss of blood supply to the femoral head, leading to bone collapse
• Referred pain — from the lumbar spine or sacroiliac joint, which can mimic true hip pathology

The Clinical Assessment

A thorough hip assessment begins with a detailed history — understanding the nature, location, and onset of pain, aggravating and relieving factors, and the impact on daily activities and function. A walking assessment (gait analysis) and physical examination follow, evaluating range of motion, strength, and specific provocation tests.