Lower limb
Iliofemoral ligament (Y-ligament of Bigelow / Bertin)
Ligamentum iliofemorale (Ligament van Bertin / Y-ligament)
- Origin
- Anterior inferior iliac spine (AIIS) and acetabular rim
- Insertion
- Intertrochanteric line of femur (bifurcates into lateral transverse and medial descending bands)
- Function
- Strongest ligament in the human body (tensile strength >350 kg); prevents hip hyperextension, allowing relaxed upright standing without continuous hip flexor muscle effort
- Innervation
- Femoral nerve (L2–L4)
- Movement & chain
- Becomes fully taut in hip extension, external rotation, and adduction
- Palpation
- Deep anterior hip structure, not directly palpable
- Clinical
- Hip flexion contracture resulting in compensatory lumbar hyperlordosis; utilized by paraplegic patients to stand balanced on their Y-ligaments.
- Segmental innervation
- L2–L4
- In clinical practice
- Thomas test for hip extension deficit, targeted iliopsoas/iliofemoral stretching, and gait analysis
- Region in the model
- Lower limb