Posterior Hip Arc Ligament

ligamentum arcus posterioris coxae

The posterior hip capsular arc ligament reinforces the posterior capsule during deep hip flexion, where the ischiofemoral ligament becomes slack. Its role in preventing posterior hip dislocation in seated positions (car seat, toilet) is particularly relevant in the post-hip arthroplasty setting.

Region: Thigh

Biomechanics

Function & Actions

Posterior hip stability during hip flexion; limits excessive internal rotation in flexion; supplementary to the ischiofemoral ligament.

Clinical Relevance

Clinical Notes

The posterior arc capsular ligament is repaired during capsulorrhaphy in posterior hip arthroplasty to reduce dislocation risk. Posterior hip capsular contracture of this structure produces internal rotation restriction in hip flexion, a source of posterior hip pain in athletes with hip flexion-dominant activities.

Pathology

Common Injuries & Conditions

Posterior Hip Capsular Contracture

Fibrosis of the posterior arc ligament producing internal rotation restriction in hip flexion, contributing to posterior hip pain and femoroacetabular impingement mechanics.