Anomalous Origin of Obturator Artery from Inferior Epigastric Artery

Abstract

During routine cadaver dissection at Oakland University William Beaumont School of Medicine, an aberrant Obturator artery (OBA) was observed originating from the inferior epigastric artery (IEA). Typically, OBA originates from the anterior division of the internal iliac artery (IIA). When it originates from the IEA, it passes over the pelvic brim and places the individual at risk for hemorrhage during surgery in that region or after pelvic trauma. This phenomenon is called ‘corona mortis.’ The objective of this study is therefore to characterize how many OBAs arise from IIA and how many arise from aberrant branching patterns, with a focus on those which arise from IEA. The origin of the OBA was studied in 24 formalin fixed cadavers (13 female, 11 male, average age 80) which had been dissected by first year medical students. To confirm identification, the obturator nerve was first identified passing into the obturator canal in each cadaver, and then the main arterial contribution passing into the obturator canal was identified. The OBA was found to originate from the anterior division of the IIA in 28 pelvic halves (58%). In 12 (25%) cases , OBA was found to arise from the IEA. In 7 (15%) cases, it arose from other locations such as the posterior division of the internal iliac artery (6) or as a branch of the superior gluteal artery (1). There was one hemisected pelvis in which the accessory OBA arising from the IEA was the same size as the OBA contribution from the anterior division of IIA. We found that 60% of the aberrant OBAs were on the right and 40% on the left. There were 13 aberrant OBAs in the female cadavers in contrast to 6 found in males. Literature review by the authors reveals widely varying estimates for the origin of OBAs. Jakubowicz et al (1996) describe incidence of OBA from IEA as only 2.6%, Mahato (2009) reports incidence at 8%, and Pai et al (2009) report incidence of 14%. Additionally, Pai et al found that this aberrance was more common in males than females, the opposite of the present findings. Furthermore, they demonstrated a similar pattern of variances of OBA arising from external iliac artery and IEA on the right (26.5%) vs left (16.3%).