The posterior portion, known as the iliac tuberosity, is elevated and rough, for the attachment of the posterior sacroiliac ligaments and for the origins of the sacrospinalis and multifidus.
The rear section, referred to as the iliac tuberosity, is prominent and irregular in shape, providing a surface for the posterior sacroiliac ligaments to attach and serving as an origin point for the sacrospinalis and multifidus muscles.