The posterior hip recess is the posteroinferior synovial extension of the hip joint capsule between the femoral neck and the posterior inferior capsule, inferior to the ischiofemoral ligament. It accommodates hip flexion by allowing capsular relaxation posteriorly and is the region that becomes distended in posterior hip effusion. The sciatic nerve lies immediately posterior to this recess, separated by the posterior capsule and the obturator externus tendon.
The posterior hip recess is the target for posterior hip joint aspiration and corticosteroid injection when performed from a posterolateral approach, typically guided by ultrasound or fluoroscopy. Posterior labral tears and ganglion cysts communicating with the posterior recess produce posterior hip pain that may be difficult to distinguish from sciatic nerve pathology. In hip arthroscopy, the posterolateral portal accesses this posterior space for labral assessment and repair. Loose bodies in the posterior hip recess may be missed on standard AP X-ray and require CT or MRI for identification.
Osteochondral fragments from posterior labral or acetabular rim injury settle in the posterior hip recess, producing mechanical posterior hip pain with occasional locking, best demonstrated on MRI or CT arthrography and removed arthroscopically through the posterolateral portal.
A paralabral cyst communicating with the posterior hip recess from a posterior labral tear produces deep posterior hip pain and external rotation weakness from sciatic nerve irritation by the enlarging cyst, managed by labral repair with concurrent cyst decompression.
