Abdominal Viscera: Part I Flashcards
where is esophagus located in abdomen?
enters abdomen at diaphragmatic hiatus: TV10
courses ~1inch, enters stomach at TV11
phrenicoesophageal ligament
attaches esophagus to diaphragm; allows for independent mvmt of diaphragm and esophagus; prevents herniation of esophagus into thorax
mesoesophagus
mesentary of esophagus - only associated with abdominal portion of esophagus
constrictions of esophagus
- cervical: cricopharyngeus muscle
- thoracic: due to arch of aorta and left primary bronchus
- diaphragmatic: prevents reflux of food/acid into esophagus
vascular supply of esophagus
AA: left gastric a.
vv: left gastric v.
esophageal varices
left gastric esophageal vv. anastomose with one another around the distal esophagus. left gastric v. drains into hepatic portal v; the esophageal veins drain to the SVC. Site of porto-caval anastamoses with portal hypertension
where do esophageal lymph nodes drain?
left gastric lymph nodes –> celiac lymph nodes
hiatal hernias: two types?
- herniation of esophagus and/or stomach through esophageal hiatus of diaphragm
a) paraesophageal: fundus of stomach herniates through esophageal hiatus anterior to esophagus. the fundus of the stomach may strangulate
b) sliding: caused by a weakening of the phrenicoesophageal ligaments allowing the cardiac and fudus of the stomach to herniate into the thorax
general features of stomach?
- fully peritonealized
- located in LUQ, however may extend inferiorly depending on fullness, body type, gender
location of stomach?
superior: diaphragm
Anterior: ventral body wall, diaphragm, left lobe of liver; supracolic compartment
posterior/inferior: omental bursa, stomach bed, lesser sac
what makes up stomach bed?
diaphragm, spleen, left kidney, suprarenal gland, pancreas, transverse colon and transverse mesocolon
curvatures of stomach?
greater curvature = left border of stomach
lesser curvature = right border of stomach
4 regions of stomach?
cardia, fundus, body, pyloric region
cardia region
portion surrounding the cardiac orifice (esophageal orifice)
- located anterior to TV11
Fundus
expanded superior portion of stomach, separated from esophagus by cardiac notch
Body of Stomach
between fundus and pyloric antrum
- the angular incisure is a sharp angulation of the lesser curvature where the body of the stomach is continuous with the pyloric region
pyloric region
pyloric antrum: funnel-shaped outflow region
pyloric canal: narrow inferior portion
Pylorus: portion containing the pyloric sphincter; normally located to the right of the midline at the LV1/LV2 level
structure of stomach wall?
- serosa
- muscular layer: outer longitudinal layer of smooth muscle, inner circular layer of smooth muscle forming pyloric sphincter, innermost oblique layer of smooth muscle
- mucosa: arranged in gastric folds = “ruggae”- rugae are most prominent in greater curvature and form gastric canal along lesser curvature
stomach mesentaries?
lesser omentum: attached to lesser curvature
greater omentum: attached to greater curvature
blood supply to stomach?
part of foregut: celiac trunk supplies
- gastric arterial arch: courses along lesser curvature. right gastric a. is branch of proper hepatic a. left gastric a. is branch of celiac trunk
- gastroepiploic arterial arch: courses along greater curvature. right gastroepiploic a. is branch of gastroduodenal a. left gastroepiploic a. is branch of splenic a.
venous drainage of stomach?
venae comitantes, ultimately draining to portal v.
lymphatic drainage of stomach?
gastric lymph nodes along lesser curvature –> celiac lymph nodes
gastroepiploic nodes along greater curvature –> celiac lymph nodes
short gastric aa.
fundus has short gastric aa. supplied by splenic a.
General characteristics of duodenum
first 12 inches of small intestine
c shaped, courses around head of pancreas
four divisions of duodenum?
first, superior part: LV1
second, descending part: LV1-LV3
third, horizontal part: LV3
fourth, ascending part: LV3-LV2
superior part
- continuous with pylorus; anterior to LV1
- peritonealized, associated with hepatoduodenal ligament
- called “duodenal bulb” because thin-wall
descending part
- descends along right side of LV1-LV3
- retroperitoneal
- major duodenal papilla: opening for hepatopancreatic ampulla
- minor duodenal papilla: opening for accessory pancreatic duct
horizontal part
runs transversely from right to left at LV3
retroperitoneal
ascending part
ascends to the left of the vertebral column, from LV3 to LV2
retroperitoneal mostly
duodenojejunal flexure: where duodenum meets the jejunum
suspensory ligament of Treitz supports duodenojejunal flexure
anatomical of superior part
- gallbladder and liver are anterior/superior. common bile duct and portal v. are posterior. head of pancreas is inferior
anatomical of descending
- liver, gallbladder, transverse colon, small intestine lie anterior.
- right kidney, renal vessels, IVC lie posterior
- pancreas, gastroduodenal a. bile and pancreatic ducts lie medial
anatomical of horizontal
anterior: superior mesenteric vessels; root of mesentary
posterior: right psoas major, IVC, aorta, right gonadal vessels
Superior: head and uncinate process of pancreas
ascending part anatomical relationships
anterior: root of mesentery, small intestine
posterior: aorta, left psoas major
villi
folds of mucosa which increase surface area for absorption in jejunum
plica circularis
folds of mucosa and submucosa in jejunum
paraduodenal hernias
sometimes, small intestine can herniate into the para into the paraduodenal fossa created by the folds of the peritoneum. surgical repair needs to be careful not to injure the inferior mesenteric vessels which run through this region
artery supply to duodenum?
anastamosis b/w celiac trunk and SMA (junction of foregut and midgut)
what does celiac trunk branch into to feed duodenum?
- branches of the gastroduodenal a:
supraduodenal, retroduodenal, superior pancreaticoduodenal
supraduodenal artery?
supplies duodenal bulb
what supplies first part of duodenum?
retroduodenal a.
What does SMA provide to duodenum?
inferior pancreaticoduodenal aa: anterior and posterior aa.
- the superior and inferior pancreaticoduodenal aa. provide anterior and posterior arterial arcades around the duodenum and head of pancreas.
venous drainage of duodenum?
venae comitantes –> draining to portal v.
lymphatic drainage of duodenum?
anterior to pancreaticoduodenal nodes –> pyloric –> celiac lymph nodes
posterior drainage is to superior mesenter nodes
peptic ulcers?
ulcers are lesions of the mucosa of the stomach or duodenum
gastric ulcers: stomach
duodenal ulcers: most common
- perforating ulcers may cause contents to escape into greater perioteneal sac causing peritonitis
- posterior perforating ulcers of stomach wall may involve the pancreas and/or splenic a –> fatal
- perforating duodenal ulcers will often erod ethe gastroduodenal a.
features of jejunoileum
begins at duodenojejunal junction, terminates at ileocecal junction
- peritonealized
- 6-7 meters long
- jejunum mostly in LUQ
- ileum mostly in RLQ and false pelvis
mesentery proper
root of the mesentery - where mesentery proper attaches to posterior body wall
- extends from left side of LV2 to the right sacroiliac joint
- crosses duodenum, aorta, IVC, ureter, psoas major, right gonadal vv.
jejunum:
increased wall thickness (thicker muscular layers, wider diameter)
increased plica circulares (circular folds)
increased vasculature (deeper red coloration)
less mesenteric fat
Fewer peyer’s patches (clumps of lymphatic tissue)
Ilium
increased mesenteric fat
increased peyer’s patches (lymphatics)
Blood supply to jejunoilium?
superior mesenteric a. (via jejunal, ileal, ileocolic branches)
arterial arcades: convoluted branch off
vasa recta: straight branch off
jejunum vs. illeum blood supply
jejunum has smaller arcades, larger vasa recta
ileium has larger arcades, smaller vasa recta
venous supply to jejunoileum?
venae comitantes to superior mesenteric v: ultimately goes to hepatic porta v.
paralytic ileus
obstruction of intestine - can result from loss of blood supply to part of the bowel
lympatic drainage of jejunoileum?
juxta-intestinal nodes –> mesenteric nodes –> superior mesenteric nodes
function of large intestine?
absorption of water, formation and storage of fecal material
components of large intestine?
cecum and appendix, ascending colon, transverse colon, descending colon, sigmoid colon, rectum and anal canal
external features common to cecum
larger diameter than small intestine
tenia coli
haustra
omental (fatty appendages)
tenia coli
- tenia colia: longitudinal muscle from cecum to rectosigmoidal junction is incomplete and present as 3 thick bands of muscle
- shorter than length of colon, so pulls into saculations called haustra
haustra
sacculations of large intestine caused by tonic contraction of tenia coli
internal features of large intestine?
plica semilunares
mucosa devoid of villi
where are cecum and appendix located?
peritonealized
located in RLQ
internal features of cecum
- Ileal orifice surrounded by superior and inferior ileocolic lips
- there is no sphincter muscle around the ileal orifice; however, contraction of the terminal ileum likely prevents reflux from cecum to ileum
appendix
- blind-ending diverticulum containing lymphoid tissue, usually in a retrocecl position
appendicitis
- inflammation of the appendix. initial appendicular pain is referred to the T10 dermatome around the umbilicus. however, infection will often spread to surrounding parietal peritoneam causing a sharp pain in the RLQ at McBurney (1/3 of distance from ASIS to umbilicus)
blood supply to appendix?
ileocolic branch of SMA :
- anterior and posterior cecal branches
- appendicular branch
vena comitantes ultimately drain to hepatic portal v.
lymphatic drainage of appendix?
ileocolic lymph nodes –> superior mesenteric lymph nodes
features of colon
- ascending, transverse, descending, sigmoid colon which arch around the small intestine from right –> left
- sigmoid colon is S shaped and descends into pelvis to rectosigmoidal junction
- right/hepatic colic flexures
- left colic/spenic flexure- phrenicocolic lig. attached here.
paracolic gutters
right: b/w ascending colon and body wall
left: b/w descending colon and body wall
mesentaries of colon?
ascending: secondarily retroperitoneal
transverse: peritonealized
descending: secondarily retroperitoneal
sigmoid: peritonealized
fusion fascias
during development, ascending and descending colon initially have a mesentery. with growth, these organs are pushed against he posterior body wall, and mesentery fuses to the peritoneaum of the posterior body wall. making them secondary retroperitoneal.
anatomical relationships of ascending colon
anterior: small intestine, greater omentum
posterior: posterior body wall; kidney
medial: small intestine
lateral: transversus abdominus
anatomy of transverse colon
anterior: anterior body wall
posterior: transverse mesocolon
superior: liver, gall bladder, stomach, spleen
inferior: small intestine
anatomical relationship of descending colon
anterior: small intestine
posterior: posterior body wall
medial: small intestine
lateral: transversus abdominus
what aa. supplies colon?
branches of SMA and IMA form an arterial loop called the marginal a.
SMA: ileocolic, right colic, middle colic
IMA: left colic, sigmoidal a.
venous drainage of colon?
venae comitantes to superior mesenteric v. –> hepatic portal v.
lymphatic drainage of colon?
paracolic nodes –> right/middle colic nodes –> superior mesenteric nodes
paracolic nodes –> left colic nodes –> inferior mesenteric lymph nodes
rectum general features
terminal 6-8” of large colon; rectosigmoidal junction (SV3)
- terminates at anal canal - anorectal junction
external features of rectum
- sacral flexure: follows curvature of sacrum
- teniae coli: spread out as a continuous layer of longitudinal muscle
- avsence of fatty omental appendages
- anorectal flexure: posteroinferior angulation as rectum passes through pelvic diaphragm
internal features of rectum?
3 transverse rectal folds: usually 2 left and one right: help to support fecal mass
ampulla: dilated, terminal portion of rectum proper, important for maintaining fecal continence
vascular supply of rectum?
aa: superior and middle rectal aa.
vv: superior and middle rectal vv.
lymphatic drainage of rectum?
- pararectal nodes drain along superior rectal a. to inferior mesenteric nodes
- pararectal nodes drain along middle rectal a. to internal iliac nodes
internal anal sphincter
surrounds superior 2/3 of canal
- sympathetic fibers L1,2 cause constriction of sphincter
- PS fibers S2-4 cause relaxation of sphincter
external anal sphincter
surrounds inferior 2/3 of canal
- voluntary muscle innervated by inferior rectal n.
anal colmns
verticle folds of mucosa containing superior rectal vessels
anal sinuses
small recesses at base of anal columns
anal valves
folds of epithelium connecting caudal ends of rectal column
pectinate line
represents change in:
1. venous drainage: S drains to superior and middle rectal vv. I drains to inferior rectal vv.
- lymphatic drainage: S drains to internal iliac lymph nodes, I drains to superficial inguinal lymph nodes
- nerve supply: S autonomic innervation, I somatic innervation
- epithelial lining: S, typical GI mucosa lining. I stratified squamous
arterial supply of rectum?
superior rectal a: superior to pectinate line
middle rectal a: forms anastomoses b/w superior and inferior rectal aa.
inferior rectal a: inferior to pectinate line
internal hemorrhoids
- dilated vv. of internal rectal venous plexus
- usually painless, may produce bright red bleeding
- may be indication of hypertension - portocaval venous anastomoses
- can also be due to pregnancy or constipation
external hemorrhoids
dilaterd vv. of external rectal venous plexus (inferior rectal vv.)
- risk factors: pregnancy, constipation, increased intra-abdominal pressure
- usually painful
