Venous Portal Circle 16
Ciro Stavolo, Raffaella Marino
L. Romano, M. Silva, S. Fulciniti, A. Pinto (eds.) MDCT Anatomy – Body 111 © Springer-Verlag Italia 2011 112 C. Stavolo, R. Marino
Left portal branch
Right portal branch Splenic vein Portal vein
Superior mesenteric vein
a
Superior Inferior mesenteric vein mesenteric vein
Colic vein
b
Suprahepatic veins
Left portal branch
Right portal branch Portal vein
Superior mesenteric vein
c
Fig. 16.1 a The portal vein is a large venous trunk that collects hypo-oxygenated blood from the sub- diaphragmatic portion of the gastrointestinal tract, spleen, pancreas, and gallbladder. b At the lev- el of the pancreatic head, the portal trunk is formed by the confluence of three major abdominal veins: superior mesenteric vein, inferior mesenteric vein, and splenic vein. c The superior mesen- teric vein is the first branch of the portal confluence. It is localized in the mesenterial adipose tis- sue, which lies in the folds of the mesenterial fan, and crosses the horizontal portion of the duo- denum, reaching the portal trunk directly. It receives blood from the intestinal mesenteric veins and the ileo-colic, middle colic, and pancreaticoduodenal veins 16 Venous Portal Circle 113
Splenoportal venous axis Splenic vein
a
Pancreas Inferior vena cava
Abdominal Splenic vein aorta
b
Left portal branch Portal vein
Superior mesenteric vein
Inferior mesenteric vein
c
Fig. 16.2 a The splenic vein is the third branch of the portal trunk and arises from the splenic hilum. b It horizontally passes through the supramesocolic abdominal space and is confined by the gastric body and pancreatic body and tail. c The inferior mesenteric vein is the second branch of the por- tal vein but in some individuals drains directly into the splenic vein. It is smaller than the superi- or mesenteric vein and passes parallel to the homonymous artery. The left colic vein, sigmoid veins, and superior hemorrhoidal veins drain into the inferior mesenteric vein 114 C. Stavolo, R. Marino
Superior mesenteric vein
Inferior vena cava Abdominal aorta
a
Left colic vein
b
Gastric vein
Portal vein Splenic vein
c
Fig. 16.3 a The superior mesenteric vein passes within the mesenterial fan, the large peritoneal re- flection that suspends the loops of the small intestine, to collect blood from the intestinal veins. At the level of the mesenterial root, the superior mesenteric vein drains into the portal trunk, crossing the third portion of the duodenum and the uncinate process of the head of the pancreas. b Tribu- taries of the superior mesenteric vein are the intestinal-mesenteric, ileocolic, middle colic, and pan- creaticoduodenal veins. c The portal trunk divides into its main branches at the liver hilum: the right branch (larger than the left branch) supplies the right hepatic and caudate lobes, while the left branch supplies the lateral hepatic lobe 16 Venous Portal Circle 115
Left portal vein branch
Main portal vein Right portal vein branch
a
Portal vein Inferior vena cava
b
Portal vein Gastric vein
Right segmentary intraepatic branch Splenic vein
c
Fig. 16.4 a At the level of the porta hepatis, the portal vein is enveloped by the hepatoduodenal lig- ament, a wide peritoneal fold covering hepatic hilar structures. This ligament also envelops the he- patic artery, main biliary duct, and lymph nodes. At the hepatic hilum, the portal trunk divides in- to right and left branches. b The left and right portal branches form the main portal intraparenchy- mal vessels of the liver. At all sizes and subdivisions, branches of the hepatic artery, portal vein, and bile ducts pass in close proximity to one another. Interlobular branches of the hepatic artery and portal vein form hepatic sinusoids, which collect into central veins and finally into the supra- hepatic venous system. c Based on its arterial and portal vascular supply, the liver parenchyma is divided in eight segments, each drained by its own bile duct and hepatic vein branch