Which ligament of the hip joint is the strongest and prevents excessive extension and external rotation of the thigh?

Explanation

## Hip Joint Ligaments **Key Point:** The iliofemoral ligament (also called the Y-ligament of Bigelow) is the strongest ligament of the hip joint and is crucial for stability in extension and external rotation. ### Structural Features **High-Yield:** The iliofemoral ligament: - Originates from the anterior inferior iliac spine (AIIS) and iliopectineal eminence - Inserts on the intertrochanteric line of the femur - Forms an inverted Y shape, with medial and lateral bands - Prevents excessive hip extension (major restraint in standing) - Prevents excessive external rotation - Bears the most load during weight-bearing and standing ### Comparative Hip Ligament Anatomy | Ligament | Origin | Insertion | Primary Function | | --- | --- | --- | --- | | **Iliofemoral** | AIIS, iliopectineal eminence | Intertrochanteric line | Prevents extension, external rotation | | **Pubofemoral** | Pubic crest, pectineal line | Medial femoral neck | Prevents abduction, external rotation | | **Ischiofemoral** | Ischial tuberosity | Greater trochanter | Prevents internal rotation | | **Ligamentum teres** | Acetabular notch | Fovea of femoral head | Carries blood vessels; minimal mechanical role | **Clinical Pearl:** The iliofemoral ligament is so strong that in standing, the hip joint can be maintained passively with minimal muscular effort—the ligament "locks" the hip in extension, which is why we can stand upright for prolonged periods without fatigue. **Mnemonic:** **ILI** (Iliofemoral) = **I**nhibits **L**arge **I**ncreases in extension.