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 posterior part, known as the iliac tuberosity, is raised and rugged, serving as a site for the attachment of the posterior sacroiliac ligaments and the origins of the sacrospinalis and multifidus muscles.