The obturator artery and vein are usually described as branches or tributaries of the internal iliac vessels although variations with connections to the external iliac or inferior epigastric vessels have been reported. Because these anomalous vessels are at risk in groin or pelvic surgeries that require dissection or suturing along the pelvic rim, we measured the frequency of these variations in 105 pelvic walls (45 in the United States and 60 in China). Our data show that 70-82% of pelvic halves and 83-90% of whole pelves had an artery, vein, or both in the variant position. Arteries were most often found in the normal position only but normal and anomalous veins were most frequently found together. These data show that it is far more common to find a vessel coursing over the pelvic rim at this site than not and have implications for both pelvic surgeons and anatomists.