Obturator artery

The obturator artery passes antero-inferiorly (forwards and downwards) on the lateral wall of the pelvis, to the upper part of the obturator foramen, and, escaping from the pelvic cavity through the obturator canal, it divides into both an anterior and a posterior branch.

Inside the pelvis
In the pelvic cavity this vessel is in relation, laterally, with the obturator fascia; medially, with the ureter, ductus deferens, and peritoneum; while a little below it is the obturator nerve.

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; a vesical branch, which runs backward to supply the bladder; and a pubic branch, which is given off from the vessel just before it leaves the pelvic cavity.

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.

Outside the pelvis
Outside the pelvis, the obturator artery divides at the upper margin of the obturator foramen, into an anterior branch and a posterior branch which encircle the foramen under cover of the Obturator externus.

Peculiarities
The obturator artery sometimes arises from the main stem or from the posterior trunk of the hypogastric, or it may spring from the superior gluteal artery; occasionally it arises from the external iliac.

In about two out of every seven cases it springs from the inferior epigastric and descends almost vertically to the upper part of the obturator foramen. The artery in this course usually lies in contact with the external iliac vein, and on the lateral side of the femoral ring (Figure A on diagram); in such cases it would not be endangered in the operation for strangulated femoral hernia.

Occasionally, however, it curves along the free margin of the lacunar ligament (Figure B), and if in such circumstances a femoral hernia occurred, the vessel would almost completely encircle the neck of the hernial sac, and would be in great danger of being wounded if an operation were performed for strangulation.