The iliofemoral ligament is a major accessory ligament of the hip joint. It plays a vital role in the hip by maintaining the position of the femur and limiting the range of motion of the hip joint. The iliofemoral ligament is one of the strongest ligaments in the human body.
The iliofemoral ligament is a Y-shaped band of dense regular fibrous connective tissue found in the anterior of the hip joint. It arises from the anterior inferior iliac spine of the ilium and divides into two distinct bands. The upper band extends laterally to attach to the upper part of the intertrochanteric line of the femur near the greater trochanter. Extending obliquely to the lower part of the intertrochanteric line is the lower band, which terminates near the lesser trochanter of the femur.
Like all ligaments, the iliofemoral ligament is made of dense irregular fibrous connective tissue. Many parallel bands of collagen protein fibers run the length of the ligament with fibroblast cells interspersed between them. Collagen proteins are the strongest proteins in the body, and their parallel arrangement makes the connection between the femur and the hipbone as strong as possible. Fibroblast cells produce new collagen fibers to strengthen, lengthen, or repair damage to the iliofemoral ligament.
The iliofemoral ligament plays several important structural roles in the hip joint. First, it connects the femur to the coxal bone and holds the femur in the correct position within the hip joint. Second, it reinforces the joint capsule of the hip joint. The hip joint is surrounded by a band of ligaments known as the joint capsule, and the iliofemoral ligament acts as an accessory ligament to support the joint capsule. Third, the iliofemoral ligament helps to reduce the range of motion at the hip joint. The hip is a ball-and-socket joint like the shoulder, but its range of motion is considerably smaller due to the amount of bodyweight it supports, the depth of its socket, and the arrangement of its ligaments. Specifically, the iliofemoral ligament limits the extension and hyperextension of the hip joint, holding the femur in a natural position below the hip to support the body’s weight. Gymnasts and dancers must stretch the iliofemoral ligament significantly to perform front splits and any other movement requiring hyperextension of the hip.