The iliac crest is the curved superior border of the ilium, the largest of the three bones that merge to form the os coxa, or hip bone. It is located on the superior and lateral edge of the ilium very close to the surface of the skin in the hip region. When a person places their hands on their hips, it is the skin above the iliac crest that they rest their hands on.
At its anterior, the iliac crest begins as a pointed bony process known as the anterior superior iliac spine. From the anterior superior iliac spine, the iliac crest continues around the superior edge of the ilium as a flattened enlargement of the ilium. At the posterior end of the ilium, the iliac crest narrows before terminating at another bony process known as the posterior superior iliac spine.
Many different muscles of the trunk and thigh attach to the iliac crest. The tensor fasciae latae and sartorius muscles of the thigh have their origins at the anterior superior spine. The internal and external oblique muscles and transverse abdominis muscle of the abdomen arise from tendons along the anterior edge of the iliac crest. The latissimus dorsi muscle forms one of its many origins along the posterior edge of the iliac crest, while the posterior superior spine gives rise to the gluteus maximus muscle of the buttock.
The iliac crest is one of the most important skeletal landmarks in the entire body. It represents a significant portion of the dividing line between the abdomen and the pelvis and is used clinically to find the L4 vertebra to perform lumbar punctures. The iliac crest is easily palpated from the body’s exterior, making it an easily identifiable landmark. The iliac crest also lends itself to bone grafting and bone marrow transplants thanks to its proximity to the body’s surface and the large amount of bone tissue and red bone marrow found in the ilium.