The iliofemoral ligament is a ligament of the

hip joint In vertebrate anatomy, hip (or "coxa"Latin ''coxa'' was used by Celsus in the sense "hip", but by Pliny the Elder in the sense "hip bone" (Diab, p 77) in medical terminology) refers to either an anatomical region or a joint. The hip region is ...

which extends from the

ilium Ilium or Ileum may refer to: Places and jurisdictions * Ilion (Asia Minor), former name of Troy * Ilium (Epirus), an ancient city in Epirus, Greece * Ilium, ancient name of Cestria (Epirus), an ancient city in Epirus, Greece * Ilium Building, a ...

to the

femur The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates wit ...

in front of the joint. It is also referred to as the Y-ligament (see below). the ligament of Bigelow, the ligament of Bertin and any combinations of these names. With a force strength exceeding 350 kg (772 lbs), 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.

Structure

Arising from the anterior inferior iliac spine and the rim of the

acetabulum The acetabulum (), also called the cotyloid cavity, is a concave surface of the pelvis. The head of the femur meets with the pelvis at the acetabulum, forming the hip joint. Structure There are three bones of the ''os coxae'' (hip bone) tha ...

, the iliofemoral ligament spreads obliquely downwards and laterally to the intertrochanteric line on the anterior side of the

femoral head The femoral head (femur head or head of the femur) is the highest part of the thigh bone ( femur). It is supported by the femoral neck. Structure The head is globular and forms rather more than a hemisphere, is directed upward, medialward, and a ...

. It is divided into two parts or bands which act differently: the transverse part above, is strong and runs parallel to the axis of the

femoral neck The femoral neck (femur neck or neck of the femur) is a flattened pyramidal process of bone, connecting the femoral head with the femoral shaft, and forming with the latter a wide angle opening medialward. Structure The neck is flattened from ...

. The descending part below, is weaker and runs parallel to the

femoral shaft The body of femur (or shaft of femur) is the almost cylindrical, long part of the femur. It is a little broader above than in the center, broadest and somewhat flattened from before backward below. It is slightly arched, so as to be convex in front ...

. As the lateral portion is twisted like a screw, the two parts together take the form of 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.

Function

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

pressed into the acetabulum. As the hip 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 Ballet () is a type of performance dance that originated during the Italian Renaissance in the fifteenth century and later developed into a concert dance form in France and Russia. It has since become a widespread and highly technical form ...

style requires a great deal of flexibility in this ligament. As does the front split where the rear leg is hyper-extended at the hip. Many externally rotate the rear leg while doing a front split, this external rotation when the hip is not flexed stretches the ligament even more. This "martial arts split" is distinguished by the rear knee pointing outward sideways (usually the foot along with it) rather than pointing straight down with the patella facing the floor, in a pure extension front split.

Additional images

File:Gray341.png, Left hip-joint, opened by removing the floor of the acetabulum from within the pelvis. File:Gray436.png, The Obturator externus. File:Spagat gymnastics.jpg, A front split requires mobility in the ligament to adequately extend the rear hip joint. File:Överspagat.jpg, Front oversplits require even more mobility to attain proper hip hyperextension.

References

External links

* () *
hip/hip%20ligaments/ligaments3
at the Dartmouth Medical School's Department of Anatomy {{Authority control Ligaments of the lower limb