The middle suprarenal artery arising from the superior mesenteric artery.

We observed a rare case of the middle suprarenal artery branching out from the superior mesenteric artery in a 78-year-old male. This atypical artery enters the right suprarenal gland that was also supplied by the superior and the inferior suprarenal arteries as usual. In embryonic stages, vasculature of the vitelline system and the gonadal system is differentially organized. The superior mesenteric artery has been generally thought to be pure vitelline, since there has been no evidence that the superior mesenteric artery supplies other organs than digestive. We then speculate that the present middle suprarenal artery is a remnant of the embryonic gonadal artery from the superior mesenteric artery, whereas a stem artery to the testis disappeared. Surgeons should take notice of the middle suprarenal artery when operations are conducted around the superior mesenteric artery.