The iliofemoral ligament
is a ligament
of the hip joint
which extends from the ilium
to the femur
in front of the joint. It is also referred to as the Y-ligament
(see below) or the ligament of Bigelow
, and any combinations of these names.
With a tensile strength exceeding 350 N, the iliofemoral ligament is not only stronger than the two other ligaments of the hip joint, the ischiofemoral and the pubofemoral, but also the strongest ligament in the human body and as such is an important constraint to the hip joint.
Arising from the anterior inferior iliac spine
and the rim of the acetabulum
, the iliofemoral ligament spreads obliquely downwards and lateralwards to the intertrochanteric line
on the anterior side of the femoral head
. It is divided into two parts or bands who act differently: The transversal part above, is strong and runs parallel to the axis of the femoral neck
. The descending part below, is weaker and runs parallel to the femoral shaft
. As the lateral portion is twisted like a screw, the two parts together take the form an inverted Y.
it is intimately connected with the joint capsule, and serves to strengthen the joint by resisting hyperextension. Its upper band is sometimes named the iliotrochanteric ligament. Between the two bands is a thinner part of the capsule. In some cases there is no division, and the ligament spreads out into a flat triangular band which is attached to the whole length of the intertrochanteric line.
In a standing posture, when the pelvis
is tilted posteriorly, the ligament is twisted and tense, which prevents the trunk from falling backwards and the posture is maintained without the need for muscular activity. In this position the ligament also keeps the femoral head
pressed into the acetabulum.
As the thighs flexes, the tension in the ligament is reduced and the amount of possible rotations in the hip joint is increased, which permits the pelvis to tilt backwards into its sitting angle. Lateral rotation and adduction in the hip joint is controlled by the strong transversal part, while the descending part limits medial rotation.
Turnout used in the classical ballet style requires a great deal of flexibility in this ligament.
- Platzer, Werner (2004). Color Atlas of Human Anatomy, Vol 1: Locomotor system. 5th, Thieme. (ISBN for the Americas 1-58890-159-9.)
- (2006). Thieme Atlas of Anatomy. Thieme. (ISBN for the Americas 1-58890-419-9)