The ischiofemoral ligament winds around the posterior femoral neck, reinforcing the posterior hip capsule. It is the primary restraint against hip internal rotation — tightening maximally with the hip flexed and internally rotated. Its contracture in the arthritic hip restricts internal rotation, producing the classic hip OA examination finding of restricted flexion-internal rotation. The ischiofemoral space — bounded by the lesser trochanter, ischial tuberosity, and ischiofemoral ligament — is compressed in ischiofemoral impingement.
| Origin | Posterior acetabular rim and ischium |
|---|---|
| Insertion | Greater trochanter and trochanteric fossa medial surface — winds around the femoral neck posteromedially |
| Actions | Resists hip internal rotation and hyperextension; the posterior hip capsule primary restraint |
|---|
The ischiofemoral ligament defines the ischiofemoral space through which the quadratus femoris passes. Narrowing of this space (from coxa valga, femoral neck anteversion, or post-arthroplasty changes) compresses the quadratus femoris muscle, producing ischiofemoral impingement syndrome with the characteristic MRI finding of quadratus femoris oedema and fat stranding.
Quadratus femoris compression from narrowed ischiofemoral space managed with activity modification, injection, and occasionally surgical decompression.
