The iliac crest is the curved ridge at the top of the pelvic bone. It forms the prominent bone of the hip. The iliac bone crest is the uppermost edge of the ilium, one of three fused bones, the ilium, the ischium, and the pubis, that together make up the pelvis.
Of the three pelvic bones, the ilium is the largest. It has a wide, flat shape, and helps to protect the delicate abdominal organs. The strong, curved edge of the ilium that forms the iliac crest gives strength to the structure of the pelvis. It is also an important structure in terms of muscular support. Several important hip, back, and abdominal muscles have their origin at this bone.
The iliac crest is a particularly important bone structure in medicine, as it contains large amounts of bone marrow. It is often used as a source of red bone marrow cells and stem cells for bone marrow transplant procedures. The iliac bone crest is usually considered to be a safer place to harvest bone marrow from than the vertebrae in the spine. Moreover, the quality of the bone marrow that can be extracted from this bone is generally considered to be of a very similar quality to spinal bone marrow.
The large amount of bone that makes up the iliac bone crest is also sometimes used as a source for bone grafts. It can provide, for example, sufficient volumes of bone for many types of facial reconstruction surgery. The iliac crest posterior region, at the back of the hip, provides particularly large volumes of bone.
Iliac crest syndrome, sometimes called the iliac crest pain syndrome, is a disorder characterized by recurrent lower back pain. The pain may occur particularly after exercise, or after sitting or standing in a particular position for a long time. Another symptom that is commonly observed with this syndrome is one iliac bone crest being lower than the other. The root cause is often an inflamed or torn iliolumbar ligament, which is the ligament that connects the iliac bone crest to the spine.
A fracture may be seen in some cases of hip trauma. These fractures are usually treated conservatively, and in a healthy adult will usually heal naturally, although pain control may be necessary. Iliac bone crest fractures are also occasionally seen as a complication in bone marrow donors, where marrow has been extracted from the ilium.