The iliac crest graft should ideally be harvested from the medial aspect because this area provides a larger volume of corticocancellous bone essential for structural support in grafting. The medial surface is more accessible and safer surgically, reducing the risk of injury to surrounding neurovascular structures such as the lateral femoral cutaneous nerve and minimizing postoperative pain. Additionally, the medial aspect offers a flat contour which facilitates graft shaping and stabilization during implantation. Harvesting from this site also preserves the lateral aspect for muscular attachments, maintaining pelvic stability.

Reference: Miller's Review of Orthopaedics, Miller, 8th Edition.