Transcript SMA and IMA
Playing Create a Lesion: • If you block one artery or vein, the body is full of backup routes to get around the blockage! • Applies to both the arterial aystem and the venous system Beginning with the… Arterial System: Only one valve in the Arterial System = Aortic Valve Pictures below are taken from Netter, I apologize for not having the corresponding plates for Grant or Clemente SMA and IMA • • • Block the middle colic Artery: Will it Die? NO! The right colic artery forms an ARCADE and anastamoses with the middle colic artery and will allow for blood to perfuse the parts of the intestine supplied by the blocked right colic; similarly, the ileocolic artery anastameses with the right colic. Block the whole SMA… And the Inferior Mesenteric Artery will anastamose with the arcades of the SMA via the MARGINAL BRANCH (off the ascending IMA) Netter, plate 287 Celiac Trunk • • • • • • • • Block the Splenic Artery: Will the Spleen Die? NO! blood can follow the common hepatic trunk-> gastroduodenal a. -> right gastroepiploic a.-> left gastroepiploic a. -> splenic a.and the short gastric arteries. Block the gastroduodenal a. Will the greater curvature die? NO! Reverse of above. Block the gastroduodenal and splenic a. Will the greater curvature die? NO! Left gastric a. anastamoses at the fundus of the stomach with the short gastric arteries off the splenic; gastroepiploics can then deliver to the gastroduodenal. If the entire celiac trunk is blocked? Pancreatico-duodenal arteries connect the system to the SMA!! The Ant. and Post. SUPERIOR pancreatico-duodenal arteries branch from the gastroduodenal a. and the Ant. and Post. INFERIOR pancreatico-duodenal arteries branch off the SMA to all anastamose. Netter, plate 282 Connecting the Thorax and the Abdomen • Assuming the abdominal aorta has been blocked there are two routes… L. Common Carotid a. R. Common Carotid a. L. Subclavian a. A. B. Anterior Wall Aorta feeds the subclavians -> internal thoracic arteries (run in the superficial fascia just inferior and lateral to the sternum) -> superior epigastric arteries (simply a name change of the internal throacics at the diaphragm) -> inferior epigastrics -> external iliac -> common iliac -> abdominal aorta Posterior Wall Aorta feeds the subclavians -> vertebral and cervical (ascending and deep) arteries which meet in the neck -> anterior and posterior spinal arteries which run down the spine -> send off intercostals branches, lumbar arteries, sacral arteries -> internal iliac arteries -> common iliac arteries -> abdominal aorta Netter plates 248, 176 may help with A. Netter 218, 219 may help with B. R. Subclavian a. To the heart Internal Thoracic Artery Superior Epigastric Artery Common Iliac A. Inferior EpiGastric Artery External Iliac A. Internal Iliac a. Absolutely no credit can be given for this drawing Venous System: 2 flavors -> Caval and Portal See problems because the lymphatics accompany the venous system closely. The lymphatics collect the junk out of the blood and increase the likelihood of infection, cancer etc. Cancerous lymph nodes or inflamed swollen lymph nodes will apply pressure to surrounding tissue; since veins are thin walled they are more likely than arteries to be compressed. Also, hepatic dysfunction can lead to novel and abnormal venous return 1. caval venous system: connections with-in one area (abdomen) or between two area (abdomen and thorax) mirror the arterial system • If the IVC is blocked? Will you die? • NO! you can use vessels of the anterior or posterior wall 2. Portal Venous system: drains the mesentery system and filters through the liver • If blocked before the liver it will follow the above 3.Portal caval shunts for when the liver is not working properly: decreased portal venous return, increased venous pressure in the mesentery a. gastric veins (caval) to esophageal veins (portal) pathological presentation: esophageal verices -> can result in acute hemorrhage b. Recanulization of the ligamentum teres pathological presentation: capitas medusae ligamentum teres (caval) anastamoses with epigastric veins (portal) at umbilicus c. Superior Rectal vein (off SMA, portal) neovascularizes with Middle and Inferior Rectal Veins (off IVC, caval) pathological presentation is hemorrhoids d. left splenic vein (of portal system) to left renal vein (of caval system ) splenorenal ligament recanulizes e. lumbar plexus of veins (with cxn to azygous and the SVC) neovascularizes to SMV and IMV neovascularization between colonic venous plexus and lumbar venous plexus Netter, Plate 293