Gastrointestinal Anatomy + Blood Supply B&B Flashcards
(24 cards)
what are the intraperitoneal structures? (7)
- stomach
- appendix
- liver
- spleen
- 1st part of duodenum + jejunum + ileum
- transverse + sigmoid colon + part of rectum
- tail of pancreas
what are the retroperitoneal structures? (5)
- aorta + IVC (rupture = retroperitoneal bleed!)
- kidneys
- 2nd/3rd portion of duodenum
- ascending + descending colon + part of rectum
- head + body of pancreas
opening between greater and lesser sac of peritoneal cavity
epiploic foramen (Omental, Winslow’s)
where is the pectinate line found?
aka dentate or anocutaneous line: part of anal canal where columnar epithelium (from hindgut) meets stratified squamous epithelium (from ectoderm)
looks like tooth-like projections on imaging
contrast the arterial supply, venous supply, lymph drainage, and innervation above and below the pectinate line
part of anal canal where columnar epithelium (from hindgut) meets stratified squamous epithelium (from ectoderm)
above: superior rectal artery (of IMA) + portal system venous drainage (may swell in portal HTN) + internal iliac nodes + visceral innervation (no pain - internal hemorrhoids)
below: inferior rectal artery (of pudendal artery, from iliac) + venous drainage to IVC + superficial inguinal nodes + somatic innervation (painful - external hemorrhoids)
what branches off the abdominal aorta? (5)
- celiac trunk
- superior mesenteric artery (SMA)
- renal arteries
- testicular/ovarian arteries
- inferior mesenteric artery (IMA)
… then split into common iliac arteries
what structures are supplied by the celiac trunk? (7)
celiac trunk supplies foregut:
1. esophagus
2. stomach
3. liver
4. gallbladder
5. spleen
6. part of duodenum
7. part of pancreas
what are the 3 main branches of the celiac trunk?
- common hepatic (R body)
- splenic (L body)
- left gastric (travels superiorly)
what arteries supply the lesser vs greater curvature of the stomach?
lesser curvature: left gastric (directly off celiac trunk) + right gastric (off proper hepatic, branch of common hepatic)
greater curvature: left gastroepiploic (off splenic artery) + right gastroepiploic (off gastroduodenal artery, branch of common hepatic)
gastric ulcers may rupture and cause bleeding from the _____ artery
posterior duodenal ulcers may rupture and cause bleeding form the _____ artery
gastric ulcers may rupture and cause bleeding from the left gastric artery
posterior duodenal ulcers may rupture and cause bleeding form the gastroduodenal artery
from where do the short gastric arteries branch, and what part of the stomach do they supply?
short gastric arteries branch from splenic artery and supply the fundus and upper cardiac portions of stomach
important - vulnerable to ischemia if splenic artery is occluded because they lack dual blood supply
which part of the stomach is vulnerable to ischemia because there is NO dual blood supply?
short gastric arteries branch from splenic artery and supply the fundus and upper cardiac portions of stomach - NO dual blood supply, vulnerable to ischemia
what is contained in the hepatoduodenal ligament? (3)
- proper hepatic artery (branch of common hepatic)
- portal vein
- common bile duct
what is the clinical use of Pringle’s maneuver?
Pringle’s maneuver = clamping the hepatoduodenal ligament during surgery to control liver bleeding
hepatoduodenal ligament contains proper hepatic artery + portal vein + common bile duct
if this maneuver DOES NOT control liver bleeding, bleeding comes from IVC or hepatic vein
which structures are supplied by the superior mesenteric artery (SMA)? (7)
SMA supplies midgut:
1. distal duodenum
2. jejunum
3. ileum
4. cecum
5. appendix
6. ascending colon
7. first 2/3 of transverse colon
what branches off the superior mesenteric artery (SMA) on the R vs L side of body?
right side of body branches: middle colic, right colic, ileocolic arteries
left side of body branches: ileal and jejunal arteries which form an arcades (anastomoses) [+ vasa recta arteries extending from arcades]
what is the cause of SMA syndrome?
SMA (superior mesenteric artery) courses over the distal 1/3 of duodenum and may cause bowel obstruction
duodenum pressed between SMA and aorta, classically in a patient with recent massive weight loss (fat pad shrinks)
what structures are supplied by the inferior mesenteric artery (IMA)? (3)
IMA supplies hindgut:
1. last 1/3 of transverse colon]
2. descending colon
3. sigmoid colon
where is there an abdominal collateral between the celiac trunk and SMA?
superior pancreaticoduodenal (celiac branch) + inferior pancreaticoduodenal (SMA branch)
therefore, gastric ischemia due to vessel occlusion is very unlikely
where is there an abdominal collateral between the SMA and IMA?
Marginal artery of Drummond receives branches from middle (SMA) and left (IMA) colic arteries - courses along transverse and descending colon
can become ischemic due to shock, but very unlikely from vessel occlusion
where is there an abdominal collateral between the IMA and iliac artery?
superior rectal artery (from IMA) + middle rectal artery (from iliac artery)
therefore, rectal ischemia from occlusion is very unlikely
name 3 places in the abdomen where collateral circulation makes ischemia from vessel occlusion highly unlikely?
- stomach: superior pancreaticoduodenal (celiac trunk) + inferior pancreaticoduodenal (SMA)
- Marginal artery of Drummond: branches from middle (SMA) and left (IMA) colic arteries
- rectum: superior rectal artery (IMA) + middle rectal artery (iliac artery)
mesenteric ischemia vs ischemic colitis
mesenteric ischemia = ischemia of intestines, that of small intestine is most severe, often life threatening
ischemic colitis = ischemia of colon, may spontaneously resolve, less severe
what are the 2 watershed areas of the colon that are most at risk for ischemia in shock or hypo-perfusion?
- splenic flexure: supplied by smallest branches of marginal artery of Drummond (furthest from SMA or IMA)
- rectosigmoid junction: supplied by narrow branches of IMA
pt at risk = ICU patients with hypotension or on pressors
