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 comp ...

that passes antero-inferiorly (forwards and downwards) on the lateral wall of the

pelvis The pelvis (plural pelves or pelvises) is the lower part of the trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis, or pelvic skeleton). The ...

, 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, 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; medially, with the ureter,

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 w ...

, 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 mes ...

; 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, which supply the bone and the Iliacus, 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 and ...

; 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 en ...

; 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 obturator canal 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 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 tubercle Obtur ...

and then curves downward along the anterior margin of the

. It distributes branches to the obturator externus,

pectineus The pectineus muscle (, from the Latin word ''pecten'', meaning comb) is a flat, quadrangular muscle, situated at the anterior (front) part of the upper and medial (inner) aspect of the thigh. The pectineus muscle is the most anterior adductor ...

, adductors, and gracilis muscle, 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 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, where it anastomoses with the anterior branch. It gives twigs to the muscles attached to the ischial tuberosity and anastomoses with the inferior gluteal artery. It also supplies an articular branch which enters the hip-joint through the acetabular notch, ramifies in the fat at the bottom of the

acetabulum The acetabulum (), also called the cotyloid cavity, is a concave surface of the pelvis. The head of the femur meets with the pelvis at the acetabulum, forming the hip joint. Structure There are three bones of the ''os coxae'' (hip bone) that c ...

and sends a twig along the

ligament of head of femur In human anatomy, the ligament of the head of the femur (round ligament of the femur, ligamentum teres femoris, the foveal ligament, or Fillmore’s ligament) is a ligament located in the hip. It is triangular in shape and somewhat flattened. The ...

(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, and occasionally it arises from the external iliac. In about two out of every seven cases it arises from the

inferior epigastric Inferior may refer to: * Inferiority complex * An anatomical term of location * Inferior angle of the scapula, in the human skeleton * ''Inferior'' (book), by Angela Saini * ''The Inferior'', a 2007 novel by Peadar Ó Guilín See also *Junior ( ...

and descends almost vertically to the upper part of the

. The artery in this course usually lies in contact with the

external iliac vein External may refer to: * External (mathematics), a concept in abstract algebra * Externality In economics, an externality or external cost is an indirect cost or benefit to an uninvolved third party that arises as an effect of another party ...

, and on the lateral side of the femoral ring ''(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 ligame ...

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