Watercolor drawing showing vegetative growths on the aortic sigmoids, a firm clot in the axillary artery with discoloration of the skin over it. Drawn by Thomas Godart, 1870. The sigmoid arteries run obliquely downward and to the left behind the peritoneum and in front of the Psoas major, ureter, and internal spermatic vessels. Their branches supply the lower part of the descending colon, the iliac colon, and the sigmoid or pelvic colon; anastomosing above with the left colic, and below with the superior hemorrhoidal artery.