AN17.1-3 | Hip Joint — Summary & Reflection

REFLECT

Compare the hip joint and the shoulder joint — both are ball-and-socket joints. In what ways does the hip sacrifice mobility for stability? Consider the depth of the socket, number and strength of ligaments, and the role of the labrum. Why does this trade-off make clinical sense given the function of each joint?

KEY TAKEAWAYS

• Hip joint = ball-and-socket (spheroidal) synovial joint; deep socket + strong ligaments = most stable joint (unlike shoulder)
• Iliofemoral ligament (Y-ligament) = strongest ligament in the body; resists extension + lateral rotation
• Blood supply to femoral head: retinacular branches of medial circumflex femoral artery; torn in displaced intracapsular fractures → AVN
• Posterior dislocation (most common): flexed, adducted, internally rotated limb + risk of sciatic nerve injury → foot drop
• THR posterior approach: short external rotators detached; dislocation risk post-op if patient flexes hip >90°
• Hip pain referred to medial knee via obturator nerve; gluteus medius/minimus weakness → Trendelenburg gait