The Obturator Artery

The obturator artery is branch of the anterior division of the internal iliac artery. It arises in the pelvis and it enters the obturator canal. it divides into two branches: the anterior and posterior branch. These two branches form a vascular circle around the outer surface of the obturator membrane.

The acetabular branch reaches the hip joint and joins the ligamentum teres to supply the head of the femur; It usually supplies a small portion of the head of the femur. The other branches of the obturator membrane are muscular and supply the muscles of the medial side of the thigh.

There are some important anatomical and clinical considerations for the obturator artery.

1. The Corona Mortis: a connection between the internal iliac branch (obturator) and the external iliac or its branch, the inferior epigastric. Cadaveric studies show that the incidence of the Corona Mortis is up to 84%. However, in clinical practice, the incidence of Corona Mortis is not that high. It is predominantly a venus connection and the arterial connection is much less. Its location on the superior pubic ramus is variable. It is about 3–7 cm from the symphysis pubis. It is located behind and on top of the superior pubic ramus and one must be careful with lateral dissection of the superior pubic ramus. Corona Mortis means the “crown of death”. It is susceptible to injury in pelvic trauma and pelvic surgery. Injury to the Corona Mortis may lead to significant hemorrhage which may be difficult to control.

2. Acetabular screw position in total hip arthroplasty. For the safe insertion of acetabular screws in total hip arthroplasty, the acetabular anatomy utilizes a quadrant system. A line drawn from the anterior superior iliac spine through the center of the acetabulum separates the anterior and posterior quadrant. This line is divided, or bisected, perpendicular at its midpoint to create four quadrants. The obturator vessels are found in the anterior-inferior quadrant. The anterior superior quadrant contains the external iliac vessels. The obturator artery may be at risk of injury from placement of a retractor underneath the transverse acetabular ligament, especially if the retractors are placed too anteriorly during total hip replacement. The transverse acetabular ligament bridges the acetabular notch. The ligament converts the notch into a tunnel. The blood vessels enter the joint through this tunnel. The branches of the obturator artery may bleed in the area of the transverse acetabular ligament. If the transverse acetabular ligament needs to be transected, then the surgeon will want to release the ligament on its posterior half in order to avoid bleeding from the obturator artery.

3. Reduction of an “open book” fracture of the pelvis can be done utilizing reduction clamps. It is probably safe to insert the reduction clamp through the medial side of the foramen, away from the neurovascular bundle, which is located laterally.