VASCULAR ANATOMY OVER THE ILIOPUBIC RAMI IN FEMALE CADAVERS

P. Drewes, S. Marinis, J Schaffer, M. Corton

University of Texas Southwestern Medical Center at Dallas, Dallas, TX

OBJECTIVE:  The objective of this study was to characterize the anatomy of the vessels that pass over the superior border of the iliopubic rami medial to the external iliac vessels.
MATERIALS AND METHODS:  Detailed dissections of the retropubic space were performed in twelve fresh-frozen adult female cadavers.  Vessels that crossed over the iliopubic rami, commonly referred to as accessory obturator vessels, were carefully dissected and their course followed from the obturator canal (OC) to the inferior epigastric or external iliac vessels. All vessels equal to or greater than one millimeter in width were measured and their anatomic location noted. The distances between the OC and the midline of the posterior pubic symphysis and the upper border of the iliopectineal line (Cooper’s ligament) were recorded.
RESULTS: Accessory obturator vessels, ranging in diameter from 1 to 6 mm, were noted in the following proportions: eight of twelve (66.7%) cadavers had accessory obturator vessels, seven (58.3%) had accessory obturator veins, four (33.3 %) had accessory obturator arteries, three (25.0%) had both, and accessory vessels were seen bilaterally in seven (58.3%). These vessels passed over the iliopubic rami lateral to or at the level of the obturator canal.  In one cadaver, three one-millimeter veins crossed over Cooper’s ligament medial to the level of the OC, and coursed between the obturator internus muscle and the inferior epigastric vein on the right side.  The mean distance from the midline of the pubic symphysis to the inferomedial border of the OC was 5.4 cm on the right (range 4.6-6.0) and 5.3 cm on the left (range 4.5-6.1).  The mean distance from the upper portion of Cooper’s ligament to the anterior border of the OC was 1.8 cm bilaterally (range 1.5-2.6).
CONCLUSION:  Gross dissection of twelve fresh female cadavers showed that accessory obturator vessels were present in two-thirds of the specimens. Since these vessels pass over the iliopubic rami lateral to or at the level of the OC, exposing Cooper’s ligament and placing retractors to elevate the anterior abdominal wall during retropubic surgery is safest within 4.5 cm from the midline. While care should be taken to avoid injury to any vessels that cross over Cooper’s ligament, significant hemorrhage is most likely to occur from injury to the communicating vessels between the external (inferior epigastric) and internal (obturator) iliac systems; these are located lateral to or at the level of the OC. Understanding the anatomic location of these accessory obturator vessels, and the location of the obturator canal, should aid the surgeon in avoiding serious neurovascular injuries.

Key Words: accessory obturator vessels, retropubic space, iliopubic rami, obturator canal

Disclosure - Grant/Research: J. Schaffer, Cook Ob/Gyn, Lilly; Speakers Bureau: J. Schaffer, Lilly;  Advisory Board: J. Schaffer, Yamanouchi Pharma America.