Posterior superior iliac spine

Illustration of the posterior pelvis. In most persons, the posterior superior iliac spine can be easily palpated as a bony prominence at the posterior end of the iliac crest. The bone marrow needle should be inserted at the top of this prominence (at the site of the asterisk). As shown by the arrow, it should be angled in the direction of the anterior superior iliac spine, a prominence found at the anterior end of the iliac crest.