Accessory Obturator Artery
The obturator artery arises from the anterior trunk of the internal iliac artery. It descends on the lateral pelvic wall to the upper margin of the obturator foramen, where it exits the pelvis (with the obturator nerve and vein) via the obturator canal. The obturator artery divides into anterior and posterior branches. Within the pelvis the obturator artery supplies the iliac fossa, the iliacus muscle, and the bladder. Outside the pelvis the anterior branch supplies the: obturator externus, pectineus, femoral adductors, and gracilis muscles. Its posterior branch supplies those muscles attached to the ischial tuberosity. An acetabular branch enters the acetabular notch to supply the ligament of the femoral head.
In an appreciable number of cases (30%) the obturator artery arises primarily or entirely from the inferior epigastric or the external iliac arteries, to become the Accessory or Abnormal Obturator artery. An obturator artery of anomalous origin may have a very close but unpredictable relation to a femoral hernia. If a hernia medially displaces an accessory obturator artery (in relation to the femoral ring), it is at greater risk of injury when the lacunar ligament is incised to release the hernia.