The obturator artery is a branch of the

internal iliac artery The internal iliac artery (formerly known as the hypogastric artery) is the main artery of the pelvis. Structure The internal iliac artery supplies the walls and viscera of the pelvis, the buttock, the reproductive organs, and the medial compa ...

that passes antero-inferiorly (forwards and downwards) on the lateral wall of the pelvis, to the upper part of the

obturator foramen The obturator foramen (Latin foramen obturatum) is the large opening created by the ischium and pubis bones of the pelvis through which nerves and blood vessels pass. Structure It is bounded by a thin, uneven margin, to which a strong membran ...

, and, escaping from the pelvic cavity through the

obturator canal The obturator canal is a passageway formed in the obturator foramen by part of the obturator membrane and the pelvis. It connects the pelvis to the thigh. Structure The obturator canal is formed between the obturator membrane and the pelvis. Th ...

, it divides into both an anterior and a posterior branch.

Structure

In the pelvic cavity this vessel is in relation, laterally, with the

obturator fascia The obturator fascia, or fascia of the internal obturator muscle, covers the pelvic surface of that muscle and is attached around the margin of its origin. Above, it is loosely connected to the back part of the arcuate line, and here it is conti ...

; medially, with the

ureter The ureters are tubes made of smooth muscle that propel urine from the kidneys to the urinary bladder. In a human adult, the ureters are usually long and around in diameter. The ureter is lined by urothelial cells, a type of transitional epit ...

ductus deferens The vas deferens or ductus deferens is part of the male reproductive system of many vertebrates. The ducts transport sperm from the epididymis to the ejaculatory ducts in anticipation of ejaculation. The vas deferens is a partially coiled tube ...

, and

peritoneum The peritoneum is the serous membrane forming the lining of the abdominal cavity or coelom in amniotes and some invertebrates, such as annelids. It covers most of the intra-abdominal (or coelomic) organs, and is composed of a layer of meso ...

; while a little below it is the

obturator nerve The obturator nerve in human anatomy arises from the ventral divisions of the second, third, and fourth lumbar nerves in the lumbar plexus; the branch from the third is the largest, while that from the second is often very small. Structure The o ...

. The obturator artery usually arises from the

. Inside the pelvis the obturator artery gives off iliac branches to the

iliac fossa The iliac fossa is a large, smooth, concave surface on the internal surface of the ilium (part of the three fused bones making the hip bone). Structure The iliac fossa is bounded above by the iliac crest, and below by the arcuate line. It is b ...

, which supply the bone and the

Iliacus The iliacus is a flat, triangular muscle which fills the iliac fossa. It forms the lateral portion of iliopsoas, providing flexion of the thigh and lower limb at the acetabulofemoral joint. Structure The iliacus arises from the iliac fossa on ...

, and anastomose with the

ilio-lumbar artery The iliolumbar artery is the first branch of the posterior trunk of the internal iliac artery. Structure The iliolumbar artery is the first branch of the posterior trunk of the internal iliac artery. It turns upward behind the obturator nerve a ...

; a vesical branch, which runs backward to supply the

bladder The urinary bladder, or simply bladder, is a hollow organ in humans and other vertebrates that stores urine from the kidneys before disposal by urination. In humans the bladder is a distensible organ that sits on the pelvic floor. Urine enters ...

; and a pubic branch, which is given off from the vessel just before it leaves the

pelvic cavity The pelvic cavity is a body cavity that is bounded by the bones of the pelvis. Its oblique roof is the pelvic inlet (the superior opening of the pelvis). Its lower boundary is the pelvic floor. The pelvic cavity primarily contains the reproduc ...

. The pubic branch ascends upon the back of the pubis, communicating with the corresponding vessel of the opposite side, and with the

inferior epigastric artery In human anatomy, inferior epigastric artery refers to the artery that arises from the external iliac artery. It anastomoses with the superior epigastric artery. Along its course, it is accompanied by a similarly named vein, the inferior epig ...

Outside the pelvis

After passing through the

and outside of the pelvis, the obturator artery divides at the upper margin of the

, into an anterior branch and a posterior branch of the obturator artery which encircle the foramen under cover of the

obturator externus The external obturator muscle, obturator externus muscle (; OE) is a flat, triangular muscle, which covers the outer surface of the anterior wall of the pelvis. It is sometimes considered part of the medial compartment of thigh, and sometimes c ...

. The anterior branch of the obturator artery is a small

artery An artery (plural arteries) () is a blood vessel in humans and most animals that takes blood away from the heart to one or more parts of the body (tissues, lungs, brain etc.). Most arteries carry oxygenated blood; the two exceptions are the pu ...

in the thigh and runs forward on the outer surface of the

obturator membrane The obturator membrane is a thin fibrous sheet, which almost completely closes the obturator foramen. Its fibers are arranged in interlacing bundles mainly transverse in direction; the uppermost bundle is attached to the obturator tubercles and ...

and then curves downward along the anterior margin of the

. It distributes branches to the

, pectineus, adductors, and

gracilis muscle The gracilis muscle (; Latin for "slender") is the most superficial muscle on the medial side of the thigh. It is thin and flattened, broad above, narrow and tapering below. Structure It arises by a thin aponeurosis from the anterior margins o ...

, and

anastomoses An anastomosis (, plural anastomoses) is a connection or opening between two things (especially cavities or passages) that are normally diverging or branching, such as between blood vessels, leaf veins, or streams. Such a connection may be norm ...

with the posterior branch and with the

medial femoral circumflex artery The medial circumflex femoral artery (internal circumflex artery, medial femoral circumflex artery) is an artery in the upper thigh that arises from the profunda femoris artery''.'' Damage to the artery following a femoral neck fracture may lead ...

. The posterior branch of the obturator artery is a small artery in the

thigh In human anatomy, the thigh is the area between the hip ( pelvis) and the knee. Anatomically, it is part of the lower limb. The single bone in the thigh is called the femur. This bone is very thick and strong (due to the high proportion of ...

and follows the posterior margin of the foramen and turns forward on the

inferior ramus of the ischium The ischium () form ...

, where it anastomoses with the anterior branch. It gives twigs to the muscles attached to the

ischial tuberosity The ischial tuberosity (or tuberosity of the ischium, tuber ischiadicum), also known colloquially as the sit bones or sitz bones, or as a pair the sitting bones, is a large swelling posteriorly on the superior ramus of the ischium. It marks th ...

and anastomoses with the

inferior gluteal artery The inferior gluteal artery (sciatic artery), the smaller of the two terminal branches of the anterior trunk of the internal iliac artery, is distributed chiefly to the buttock and back of the thigh. It passes down on the sacral plexus of nerves ...

. It also supplies an articular branch which enters the hip-joint through the

acetabular notch The acetabular notch is a deep notch in the acetabulum of the hip bone. The acetabular notch is continuous with a circular non-articular depression, the acetabular fossa, at the bottom of the cavity: this depression is perforated by numerous aper ...

, ramifies in the fat at the bottom of the acetabulum and sends a twig along the ligament of head of femur (ligamentum teres) to the head of the femur. The blood supply to the femoral head and neck is enhanced by the artery of the ligamentum teres derived from the obturator artery. In adults, this is small and doesn't have much importance, but in children whose epiphyseal line is still made of cartilage (which doesn't allow blood supply through it), it helps to supply the head and neck of the femur on its own. The articular branch is usually patent until roughly 15 years of age. In adults it does not provide enough blood supply to prevent avascular necrosis in upper femur fractures.

Variation

The obturator artery usually arises from the main stem or from the anterior trunk of the

. It may arise from the

superior gluteal artery The superior gluteal artery is the largest and final branch of the internal iliac artery. It is the continuation of the posterior division of that vessel. It is a short artery which runs backward between the lumbosacral trunk and the first sacral ...

, and occasionally it arises from the external iliac. In about two out of every seven cases it arises from the inferior epigastric and descends almost vertically to the upper part of the

. The artery in this course usually lies in contact with the external iliac vein, and on the lateral side of the

femoral ring The femoral ring is the opening at the proximal, abdominal end of the femoral canal, and represents the (superiorly directed/oriented) base of the conically-shaped femoral canal. The femoral ring is oval-shaped, with its long diameter being direc ...

''(Figure A on diagram).'' It can also pass medial to the femoral ring along the margin of the

lacunar ligament The lacunar ligament, also named Gimbernat’s ligament, is a ligament in the inguinal region. It connects the inguinal ligament to the pectineal ligament, near the point where they both insert on the pubic tubercle. Structure The lacunar ligam ...

''(Figure B).'' In either case it would be at risk of injury during the operation to repair a

femoral hernia Femoral hernias occur just below the inguinal ligament, when abdominal contents pass through a naturally occurring weakness in the abdominal wall called the femoral canal. Femoral hernias are a relatively uncommon type, accounting for only 3% of ...

, whether the hernia is reducible, incarcerated or strangulated. When the obturator artery travels along the lacunar ligament, it nearly encircles the femoral ring and can be lacerated during a femoral hernia repair. Most femoral hernias are repaired through a small (1/2 to 3/4 inch) incision in the groin area, rather than through the abdomen, so if a laceration were to occur, bleeding may not be immediately recognized and result in significant blood loss into the peritoneal cavity. Because of this danger, the anatomic variant in Figure B is sometimes referred to as the "crown of death" (corona mortis) .

Additional images

File:Gray236.png, Right hip bone. Internal surface. File:Gray404.png, Left Levator ani from within.

References

External links

* - "The Female Pelvis: Branches of Internal Iliac Artery" * () *
Variations at anatomyatlases.org

Variations at anatomyatlases.org
{{Authority control Arteries of the abdomen