The obturator artery is a branch of the anterior division of the internal iliac artery. It provides vascular supply within the pelvis and medial lower limb. 

Summary

• origin: anterior division of the internal iliac artery

• location: pelvis and lower limb

• supply: pelvic muscles, ilium, head of the femur, muscles of the medial thigh, skin

• branches: anterior and posterior branches, artery in the ligament of the femur, iliac branch, pubic branch, branch to the knee capsule

Gross anatomy

Origin

The obturator artery most often originates from the anterior division of the internal iliac artery. It travels along the obturator fascia of the pelvic sidewall, between the obturator nerve and vein, to reach the obturator foramen. It is crossed by the ureter close to its origin, and by the ductus deferens in the male.

Branches

The obturator artery has several branches which may be grouped as follows as branches in the pelvis and those within the thigh.

Branches within the pelvis:

• the nutrient artery to the ilium supplies the iliac bone and iliacus muscle

• the pubic branch of the obturator artery anastomoses with the pubic branch of the inferior epigastric artery.

It then travels through the obturator canal with the obturator nerve passing into the medial compartment of the thigh. 

Within the medial compartment of the thigh the obturator artery splits into anterior and posterior branches. These travel around the origin of the obturator externus and anastomose with one another and the medial circumflex femoral artery.

• the anterior branch supplies the adductor brevis muscle, and the skin over the medial thigh at its termination.

• the posterior branch gives another branch, the artery of the ligamentum teres which runs in the ligament of the head of the femur and eventually atrophies and becomes nonfunctional after approximately the age of seven. The posterior branch also supplies the adductor muscles and gives a small terminal branch to the capsule of the knee joint. 

Supply

The obturator artery supplies the pelvic muscles it crosses, the head of the femur, the muscles of the medial compartment of the thigh and gives a small branch to the knee capsule. The iliac branch supplies the bone and the iliacus muscle. It also has a cutaneous supply to the medial thigh.

Variant anatomy

The obturator artery may be replaced by a large pubic branch of the inferior epigastric artery. Known as an accessory, or aberrant obturator artery, it may be present in approximately 20% of cases. This occurs when a large branch of the inferior epigastric artery descends into the pelvis along the usual path of the pubic branch of the obturator artery. Most often, it lies medial to the femoral ring. However, when it lies lateral to the femoral ring, its location predisposes to injury during femoral hernia repair.

The corona mortis represents a vascular anastomosis with the inferior epigastric artery which, due to its course over the superior pubic ramus, is at risk of injury during pelvic trauma.

The obturator artery may also have an anomalous origin, arising from the:

• common iliac artery

• external iliac artery

• posterior division of the internal iliac artery 

or together with the:

• superior gluteal artery

• iliolumbar artery 

• inferior epigastric artery

It may also arise as two roots; one from the external iliac artery and the other from the iliac artery e.g. as its usual origin.