Which ligament of the hip joint is most taut in hip extension and internal rotation, and is the most commonly injured during posterior hip dislocation?

• A Pubofemoral ligament
• B Ischiofemoral ligament
• C Ligament of the head of femur (ligamentum teres)
• D Iliofemoral ligament (Y-ligament of Bigelow) ✓

Explanation

The iliofemoral ligament (Y-ligament of Bigelow) is the strongest ligament in the human body, arising from the anterior inferior iliac spine and inserting in a Y-shape on the intertrochanteric line. It is maximally taut in hip extension and internal rotation, preventing hyperextension (essential for erect bipedal stance). In posterior hip dislocations (flexion-adduction force), the femoral head tears the posterior capsule; however, the Y-ligament's anterior orientation means it becomes a primary constraint and is frequently avulsed from the iliac spine. The ischiofemoral ligament spirals posteriorly and tightens in internal rotation and extension. Ligamentum teres carries vascular supply but is not a primary stabiliser.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.