The crest of the ilium (or iliac crest) is the superior border of the wing of ilium and the superiolateral margin of the greater pelvis.

Structure

The iliac crest stretches posteriorly from the

anterior superior iliac spine The anterior superior iliac spine ( abbreviated: ASIS) is a bony projection of the iliac bone, and an important landmark of surface anatomy. It refers to the anterior extremity of the iliac crest of the pelvis. It provides attachment for the i ...

(ASIS) to the posterior superior iliac spine (PSIS). Behind the ASIS, it divides into an outer and inner lip separated by the intermediate zone. The outer lip bulges laterally into the iliac tubercle. Platzer (2004), p 186 Palpable in its entire length, the crest is convex superiorly but is sinuously curved, being concave inward in front, concave outward behind. Palastanga (2006), p 243 It is thinner at the center than at the extremities.

Development

The iliac crest is derived from endochondral bone.

Function

To the external lip are attached the ''

Tensor fasciae latae The tensor fasciae latae (or tensor fasciæ latæ or, formerly, tensor vaginae femoris) is a muscle of the thigh. Together with the gluteus maximus, it acts on the iliotibial band and is continuous with the iliotibial tract, which attaches to the ...

'', '' Obliquus externus abdominis'', and ''

Latissimus dorsi The latissimus dorsi () is a large, flat muscle on the back that stretches to the sides, behind the arm, and is partly covered by the trapezius on the back near the midline. The word latissimus dorsi (plural: ''latissimi dorsorum'') comes from ...

'', and along its whole length the ''

fascia lata The fascia lata is the deep fascia of the thigh. It encloses the thigh muscles and forms the outer limit of the fascial compartments of thigh, which are internally separated by the medial intermuscular septum and the lateral intermuscular sep ...

''; to the intermediate line, the ''

Obliquus internus abdominis The abdominal internal oblique muscle, also internal oblique muscle or interior oblique, is an abdominal muscle in the abdominal wall that lies below the external oblique muscle and just above the transverse abdominal muscle. Structure Its fib ...

''. To the internal lip, the '' iliac fascia'', the '' Transversus abdominis'',

Quadratus lumborum The quadratus lumborum muscle, informally called the ''QL'', is a paired muscle of the left and right posterior abdominal wall. It is the deepest abdominal muscle, and commonly referred to as a back muscle. Each is irregular and quadrilateral in s ...

, Sacrospinalis, and '' Iliacus''. *

Abdominal external oblique muscle The abdominal external oblique muscle (also external oblique muscle, or exterior oblique) is the largest and outermost of the three flat abdominal muscles of the lateral anterior abdomen. Structure The external oblique is situated on the latera ...

Abdominal internal oblique muscle The abdominal internal oblique muscle, also internal oblique muscle or interior oblique, is an abdominal muscle in the abdominal wall that lies below the external oblique muscle and just above the transverse abdominal muscle. Structure Its fiber ...

* ''Transversus abdominis'' muscle *

Quadratus lumborum muscle The quadratus lumborum muscle, informally called the ''QL'', is a paired muscle of the left and right posterior abdominal wall. It is the deepest abdominal muscle, and commonly referred to as a back muscle. Each is irregular and quadrilateral in sh ...

Erector spinae The erector spinae ( ) or spinal erectors is a set of muscles that straighten and rotate the back. The spinal erectors work together with the glutes ( gluteus maximus, gluteus medius and gluteus minimus) to maintain stable posture standing or ...

Iliocostalis Iliocostalis muscle is the muscle immediately lateral to the longissimus that is the nearest to the furrow that separates the epaxial muscles from the hypaxial. It lies very deep to the fleshy portion of the serratus posterior muscle. It latera ...

pars lumborum **

Longissimus The longissimus ( la, the longest one) is the muscle lateral to the semispinalis muscles. It is the longest subdivision of the erector spinae muscles that extends forward into the transverse processes of the posterior cervical vertebrae. Structu ...

pars thoracisBogduk (2005), p 106 *

* Iliacus muscle *

Fascia lata The fascia lata is the deep fascia of the thigh. It encloses the thigh muscles and forms the outer limit of the fascial compartments of thigh, which are internally separated by the medial intermuscular septum and the lateral intermuscular sep ...

* Iliac fascia * Transverse fascia

Clinical significance

The iliac crest has a large amount of red

bone marrow Bone marrow is a semi-solid biological tissue, tissue found within the Spongy bone, spongy (also known as cancellous) portions of bones. In birds and mammals, bone marrow is the primary site of new blood cell production (or haematopoiesis). It i ...

, and thus it is the site of bone marrow harvests (from both sides) to collect the

stem cells In multicellular organisms, stem cells are undifferentiated or partially differentiated cells that can differentiate into various types of cells and proliferate indefinitely to produce more of the same stem cell. They are the earliest type of ...

used in

bone marrow transplantation Hematopoietic stem-cell transplantation (HSCT) is the transplantation of multipotent hematopoietic stem cells, usually derived from bone marrow, peripheral blood, or umbilical cord blood in order to replicate inside of a patient and to produce ...

. The iliac crest is also considered the most ideal donor site for

bone grafting Bone grafting is a surgical procedure that replaces missing bone in order to repair bone fractures that are extremely complex, pose a significant health risk to the patient, or fail to heal properly. Some small or acute fractures can be cured wit ...

when a large quantity of bone is needed. For example, oral and maxillofacial surgeons will often use iliac crest bone to fill in large osseous defects of the oral cavity caused by severe periodontal disease, excess bone resorption following tooth loss, trauma, or congenital defects including alveolar clefts.Rose, Louis F.. Periodontics: Medicine, Surgery and Implants. Mosby, 072004. 26.2.2.3 The top of the iliac crests also marks the level of the fourth lumbar vertebral body (L4), above or below which

lumbar puncture Lumbar puncture (LP), also known as a spinal tap, is a medical procedure in which a needle is inserted into the spinal canal, most commonly to collect cerebrospinal fluid (CSF) for diagnostic testing. The main reason for a lumbar puncture is ...

may be performed.

Additional images

File:Iliac crest.PNG, Muscles connecting the upper extremity to the vertebral column. Left iliac crest is labeled in red. File:Gray237.png, Plan of ossification of the hip bone. File:Gray395.png, The Obliquus internus abdominis. File:Gray430.png, Muscles of the iliac and anterior femoral regions. File:Gray1124.png, The relations of the kidneys from behind. File:Orientation.PNG, Iliac crest labeled at center right. File:Slide7w.JPG, Iliac crest

References

* * *

External links

* - "Superficial muscles of the gluteal region and posterior thigh." * - "Anterior Abdominal Wall: Osteology and Surface Anatomy " * - "The Back, Posterior View" (#4)
Diagram at emedx.com

Diagram at nih.gov
{{Authority control Human anatomy Bones of the pelvis Ilium (bone)