Anatomy of Bleeding in GI Tract Flashcards
mobility of caecum
intraperitoneal - quite mobile
membrane of ascending colon
secondarily retroperitoneal
mobility of transverse colon
highly mobile, has its own mesentery
intraperitoneal
membrane of descending colon
secondarily retroperitoneal
mobility of signoid colon
intraperitoneal - quite mobile
has its onw mesentery
location of paracolic gutters
left and right (2 in total)
between lateral edge of ascending and descending colon, and abdominal wall
what are paracolic gutters potential sites for
pus collection
describe paracolic gutters
part of greater sac of peritoneal cavity
similar to subphrenic or hepatorenal recesses
where does teniae coli run
caecum to distal end of sigmoid colon
describe the splenic flexure
lies more superior than hepatic flexure
how is haustra formed
formed by tonic contraction of teniae coli
where does caecum and appendix lie
right iliac fossa
position of appendix
variable (accounts for different ways appendicitis presents);
most often retrocaecal
where is appendices orifice located
on posteromedial wall of caecum
corresponds to McBurney’s point on the anterior abdominal wall
1/3 of the way between right ASIS to umbilicus
where is maximum tenderness felt in appendicitis
appendices orifice
where does sigmoid colon lie
left iliac fossa
describe mesentery of sigmoid colon
it is long;
allowing considerable degree of movement
what is sigmoid volvulus
signed colon can twist around itself due to its great mobility
results in bowel obstruction
risks of bowel obstruction
bowel infarction in untreated
describe the abdominal aorta
midline, retroperipotneal structure
where does abdominal aorta lie
anterior to vertebral bodies and left of IVC
midline branches of abdominal aorta
3;
celiac trunk
superior mesenteric artery
inferior mesenteric artery
what do lateral branches of abdominal aorta supply
kindeys/adrenal glads
gonads
body wall (posterolateral)
bifurcation of lateral branches of abdominal aorta
bifurcate into common iliacs
further bifurcate into internal and external iliac
branches of superior mesenteric artery
appendicular ileocolic right colic middle colic inferior pancreaticduodenal superior mesenteric jejunal and iliac
branches of inferior mesenteric artery
inferior mesenteric
left colic
sigmoid colic
superior rectal
where is arterial anastomoses of mesenteric artery located
one artery between branches of superior mesenteric artery and inferior mesenteric artery
name of arterial anastomses
the marginal artery of Drummond
role arterial anastomoses of mesenteric artery
helps prevent intestinal ischaemia by providing collateral route which blood travels
artery supplying distal half of anal canal
internal iliac artery (with a degree of anastomoses)
what is haematemesis
patient vomiting blood
where does haematemesis come from
usually the upper GI tract
describe hepatic portal venous system
drains venous blood from absorptive parts of gI tract and associated organs to liver for cleaning
drainage of hepatic portal vein
drains blood from foregut, midgut and hindgut to liver for first pass metabolism
venous anastomoses between systemic and portal venous systems
portal systemic anastomoses
describe portal systemic anastomoses
presence of small collateral veins - allowing blood to flow both ways;
either into the systemic or portal venous system
no valves in these veins
very little blood flow within these collateral veins
sites of portal-systemic anastomoses
distal end of oesophagus
skin around umbilicus
rectum/anal canal
drainage of distal end of oesophagus portal-systemic anastomoses - inferior part
drains to hepatic portal vein
drainage of distal end of oesophagus portal-systemic anastomoses - superior part
drains to azygous vein
drainage of skin around umbilicus portal-systemic anastomoses
normally the ligamentum teres remains closed throughout adult life and blood flows from the skin around the umbilicus via inferior epigastric veins to the IVC
drainage of rectum/anal canal portal-systemic anastomoses
rectum and superior anal canal drains to inferior mesenteric vein
most inferior part of GI tract drains to the internal iliac veins
diversion of blood in the event of portal hypertension
blood will be diverted through the collateral veins back to the systemic venous system
collateral veins consequently have larger volume of blood -
dilate, becoming varicose
