Hip Retinacular Fibres (Posterior)

fibrae retinaculi capitis femoris posteriores

The posterior retinacular fibres are periosteal reflections of the posterior hip capsule running along the posterior femoral neck to the femoral head, transmitting the retinacular blood vessels that provide the dominant blood supply to the femoral head in adults.

Region: Thigh

Biomechanics

Function & Actions

Transmit the ascending cervical retinacular arteries (branches of the medial circumflex femoral artery) along the posterior femoral neck to the femoral head, providing the primary blood supply to the weight-bearing superior femoral head in adults.

Clinical Relevance

Clinical Notes

Disruption of the posterior retinacular fibres in intracapsular hip fractures (femoral neck fractures) devascularises the femoral head, producing avascular necrosis in 15-30% of cases. Anatomic reduction within 6-12 hours reduces AVN risk by preserving retinacular vessel flow. The posterior superior quadrant of the femoral head is the first region to become necrotic as it is furthest from the remaining blood supply.

Pathology

Common Injuries & Conditions

Femoral Head AVN from Retinacular Vessel Disruption

Intracapsular hip fracture disrupting the posterior retinacular vessels producing femoral head avascular necrosis, with risk correlated to fracture displacement and time to reduction.

Urgent Reduction of Femoral Neck Fracture

Anatomic reduction within 6-12 hours of displaced femoral neck fracture preserves the retinacular vessel integrity, reducing but not eliminating the risk of femoral head avascular necrosis.