Iliofemoral Ligament

Also known as the Y-ligament of Bigelow, it is an extraordinarily strong, thick band of fibrous tissue reinforcing the anterior capsule of the hip joint. It originates from the anterior inferior iliac spine (AIIS) and the adjacent acetabular rim, bifurcating distally into descending and transverse parts that attach along the intertrochanteric line of the femur. Its primary biomechanical role is to powerfully resist hip hyperextension, enabling a relaxed, upright standing posture with minimal muscular exertion.