The iliofemoral ligament is a thick and very tough triangular capsular

ligament A ligament is a type of fibrous connective tissue in the body that connects bones to other bones. It also connects flight feathers to bones, in dinosaurs and birds. All 30,000 species of amniotes (land animals with internal bones) have liga ...

of the

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

situated anterior to this joint. It attaches superiorly at the inferior portion of the anterior inferior iliac spine and adjacent portion of the margin of the

acetabulum The acetabulum (; : acetabula), also called the cotyloid cavity, is a wikt:concave, concave surface of the pelvis. The femur head, head of the femur meets with the pelvis at the acetabulum, forming the Hip#Articulation, hip joint. Structure The ...

; it attaches inferiorly at the

intertrochanteric line The intertrochanteric line is a line upon the anterior aspect of the proximal end of the femur, extending between the lesser trochanter and the greater trochanter. It is a rough, variable ridge. Structure The intertrochanteric line marks the bound ...

. 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

The ligament is triangular in shape, with its apex represented by its pelvic attachment. The ligament has two though outer bands; it is thinner and weaker centrally. As the lateral portion is twisted like a screw, the two parts together take the form of an inverted Y. Arising from the anterior inferior iliac spine and the rim of the

, the iliofemoral ligament spreads obliquely downwards and laterally to the

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 The femur (; : femurs or femora ), or thigh bone is the only long bone, bone in the thigh — the region of the lower limb between the hip and the ...

. 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 descending part below, is weaker and runs parallel to the femoral shaft. 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 The pelvis (: pelves or pelvises) is the lower part of an Anatomy, anatomical Trunk (anatomy), trunk, between the human abdomen, abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also c ...

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

. 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 of ...

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