ANATOMY OF THE ABDOMINAL AORTA AND INFERIOR VENA CAVA
The various vascular procedures that are carried out on the major vessels in the retroperitoneal area of the abdominal cavity make familiarity with these structures essential. Likewise, surgery of the adrenal glands and the genitourinary system invariably involves one or more of the branches of the abdominal aorta and inferior vena cava.
The blood supply to the adrenals is complicated and different on the two sides. The superior arterial supply branches from the inferior phrenic artery (1) on both sides. The left adrenal receives a branch directly from the adjacent aorta. A similar branch also may pass behind the vena cava to the right side, but the more prominent arterial supply arises from the right renal artery. The major venous return (3) on the left side is directly to the left renal vein. On the right side, the venous supply may be more obscure, as the adrenal is in close proximity to the vena cava and the venous system (2) drains directly into the latter structure.
The celiac axis (A) is one of the major arterial divisions of the abdominal aorta. It divides into the left gastric, splenic, and common hepatic arteries. Immediately below this is the superior mesenteric artery (B), which provides the blood supply to that portion of the gastrointestinal tract arising from the foregut and midgut. The renal arteries arise laterally from the aorta on either side. The left renal vein crosses the aorta from the left kidney and usually demarcates the upper limits of arteriosclerotic abdominal aneurysms. The left ovarian (or spermatic) vein (13) enters the left renal vein, but this vessel on the right side (5) drains directly into the vena cava.
In removing an abdominal aortic aneurysm, it is necessary to ligate the pair of ovarian (or spermatic) arteries (4), as well as the inferior mesenteric artery (C). In addition, there are four pairs of lumbar vessels that arise from the posterior wall of the abdominal aorta (14). The middle sacral vessels will also require ligation (12). Because of the inflammatory reaction associated with the aneurysm, this portion of the aorta may be intimately attached to the adjacent vena cava.
The blood supply to the ureters is variable and difficult to identify. The arterial supply (6, 7, 8) arises from the renal vessels, directly from the aorta, and from the gonadal vessels, as well as from the hypogastric arteries (11). Although these vessels may be small and their ligation necessary, the ureters should not be denuded of their blood supply any further than is absolutely necessary.
The aorta terminates by dividing into the common iliac arteries (9), which in turn divide into the external iliac (10) and the internal iliac (hypogastric) (11) arteries. From the bifurcation of the aorta, the middle sacral vessel (12) descends ...