Henry Gray (18251861). Anatomy of the Human Body. 1918.
above its division into the common iliacs and close to the lower border of the inferior part of the duodenum. It passes downward posterior to the peritoneum, lying at first anterior to and then on the left side of the aorta. It crosses the left common iliac artery and is continued into the lesser pelvis under the name of the superior hemorrhoidal artery, which descends between the two layers of the sigmoid mesocolon and ends on the upper part of the rectum.
Branches.Its branches are:
The Left Colic Artery (a. colica sinistra) runs to the left behind the peritoneum and in front of the Psoas major, and after a short, but variable, course divides into an ascending and a descending branch; the stem of the artery or its branches cross the left ureter and left internal spermatic vessels. The ascending branch crosses in front of the left kidney and ends, between the two layers of the transverse mesocolon, by anastomosing with the middle colic artery; the descending branch anastomoses with the highest sigmoid artery. From the arches formed by these anastomoses branches are distributed to the descending colon and the left part of the transverse colon.
The Sigmoid Arteries (aa. sigmoideæ) (Fig. 538), two or three in number, 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.
The Superior Hemorrhoidal Artery (a. hæmorrhoidalis superior) (Fig. 538), the continuation of the inferior mesenteric, descends into the pelvis between the layers of the mesentery of the sigmoid colon, crossing, in its course, the left common iliac vessels. It divides, opposite the third sacral vertebra, into two branches, which descend one on either side of the rectum, and about 10 or 12 cm. from the anus break up into several small branches. These pierce the muscular coat of the bowel and run downward, as straight vessels, placed at regular intervals from each other in the wall of the gut between its muscular and mucous coats, to the level of the Sphincter ani internus; here they form a series of loops around the lower end of the rectum, and communicate with the middle hemorrhoidal branches of the hypogastric, and with the inferior hemorrhoidal branches of the internal pudendal.
The middle suprarenal arteries (aa. suprarenales media; middle capsular arteries; suprarenal arteries) are two small vessels which arise, one from either side of the aorta, opposite the superior mesenteric artery. They pass lateralward and slightly upward, over the crura of the diaphragm, to the suprarenal glands, where they anastomose with suprarenal branches of the inferior phrenic and renal arteries. In the fetus these arteries are of large size.
The renal arteries (aa. renales) (Fig. 531), are two large trunks, which arise from the side of the aorta, immediately below the superior mesenteric artery. Each is directed across the crus of the diaphragm, so as to form nearly a right angle with the aorta. The right is longer than the left, on account of the position of the aorta; it passes behind the inferior vena cava, the right renal vein, the head of the pancreas, and the descending part of the duodenum. The left is somewhat higher than the right; it lies behind the left renal vein, the body of the pancreas and the lienal vein, and is crossed by the inferior mesenteric vein. Before reaching the hilus of the kidney, each artery divides into four or five branches; the greater number of these lie between the renal vein and ureter, the vein being in front, the ureter behind, but one or more branches are usually situated behind the ureter. Each vessel gives off some small inferior suprarenal branches to the suprarenal gland, the ureter, and the surrounding cellular tissue and muscles. One or two accessory renal arteries are frequently found, more especially on the left side