Obturator artery and veins with corona mortis not passing through the obturator canal

The obturator artery (OA) and obturator vein (OV) often exhibit anatomical variations, particularly in their origins. Corona mortis (CMOR) is a well-known type of anatomical variation; however, few studies have reported the distribution of OA after it passes through the obturator canal (OC). This case reports an abnormal OA and OVs that formed a CMOR without passing through the OC.

Variations were observed in an 81-year-old Japanese man during a gross-anatomical dissection course for students at Tokai University of Medicine in 2023.

The left OA branched from the external iliac artery via the inferior epigastric artery, coursing toward the OC with the obturator nerve (ON); however, only the ON emerged from the canal. The left OV originated in the public and internal obturator regions as OV1 and OV2, each exiting the OC separately. Furthermore, OV1 and OV2 branched and converged with the external iliac vein to form OV3 and OV4. The muscles normally supplied by OA were instead distributed by branches of the left medial circumflex femoral artery (MCFA) and femoral artery.

This is the first report of the OA and OVs not passing through the OC. Understanding the course of these vessels is essential for procedures such as pelvic lymph node dissection and endovascular aneurysm repair involving unilateral internal iliac artery interruption. The branches of the MCFA and femoral artery observed in this case may contribute to further studies on the vascular anatomy of the pelvic system.