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Posterior Iliac Crest

crista iliaca posterior

The posterior iliac crest is the posterior portion of the iliac crest from the posterior superior iliac spine (PSIS) to the posteroinferior iliac spine (PIIS), providing the attachment for the thoracolumbar fascia, the erector spinae, and the iliac portion of the posterior sacroiliac ligaments. The posterior iliac crest is the primary site for tricortical bone graft harvesting for spinal fusion and the entry point for iliosacral and posterior iliac screws.

Region: Pelvis & Hip

Clinical Relevance

Clinical Notes

The posterior iliac crest is the most common autologous bone graft donor site in orthopaedic and spinal surgery. Full-thickness tricortical graft from the posterior crest provides structurally strong graft for interbody fusion. Donor site morbidity includes persistent posterior hip pain (25% at 1 year), superior cluneal nerve injury (lateral cutaneous nerve of thigh equivalent for the buttock), haematoma, and rare sacroiliac joint disruption. Iliosacral screws for posterior pelvic ring fixation enter the iliac cortex just distal to the PSIS.

Pathology

Common Injuries & Conditions

Iliac Crest Donor Site Morbidity After Bone Graft Harvest

Posterior iliac crest bone graft harvest for spinal fusion produces persistent donor site pain in up to 25% of patients at one year from superior cluneal nerve injury, haematoma, or SI joint stress; meticulous attention to the harvest site including haemostasis and nerve identification reduces long-term donor site morbidity.