Lower Abdomen Flashcards
The stomach turns food into ____.
Chyme
Stomach is lined with ____.
Rugae
Rugae definition
temporary folds within body of stomach along longitudinal plane, help with movement (physical and enzymatic) and allow stomach to expand
Rugae are controlled by ____
Auerbach’s plexus
What are the 4 major regions of the stomach?
- Cardiac orifice
- Fundus of stomach
- Body of stomach
- Pyloric region
Of the small intestine, what is retroperitoneal and what is intraperitoneal?
Duodenum is RELATIVELY immobile and RETROperitoneal
Ileum and jejunum are tethered but mobile and INTRAperitoneal
What are the jejunum and ileum tethered by?
Mesentery proper
What are plicae circularis?
- Permanent folds in the intestine
- Help increase surface area
- Needed for absorption (surface area)
- Decrease in number as you move distally
How long is the duodenum?
25cm
Explain what parts of the duodenum are intraperitoneal vs. retroperitoneal
Duodenum is RETROPERITONEAL except:
Superior end is INTRAPERITONEAL held by hepatoduodenal ligament of lesser omentum
What is the hepatoduodenal ligament?
Part of the lesser omentum that tethers the superior end of the duodenum (which makes it intraperitoneal)
What are the 4 regions of the duodenum? Where are they relative to vertebrae?
- Superior portion - L1
- Descending portion- L2/3
- Inferior Portion- L3 *tranverse across
- Ascending portion
What part of the duodenum is intraperitoneal? Why?
Superior portion of duodenum is intraperitoneal held by hepatoduodenal ligament of lesser omentum
What is important about the superior portion of the duodenum? What vertebral level?
It’s the only portion that is intraperitoneal (held by hepatoduodenal ligament of lesser omentum)
It’s at L1
What is important about the descending portion of the duodenum? What vertebral level?
2 papilla in this portion - MAJOR and MINOR
minor is more superior than major
major papilla marks the end of the foregut
It’s at L2/3
What is important about the inferior portion of the duodenum? What vertebral level?
Anterior to Aorta and IVC
Posterior to superior mesenteric artery and vein
Transverse along L3
What is important about the ascending portion of the duodenum?
Goes up to the duodenojejunal junction
Anchored by suspensor ligament (ligament of trietz)
What is the suspensor ligament?
AKA ligament of trietz
It anchors the ascending portion of the duodenum
Vasa recta definition
Straight arteries coming off of arcades in the small intestine
Arterial arcades definition
Loops of arteries in jejunum/ileum with vasa recta coming off of them
Vasa recta trends from jejunum to ileum
Jejunum = long vasa recta Ileum = short vasa recta
Arterial arcade trends from jejunum to ileum
Jejunum = few arcades and short Ileum = many acrades and long
Plica circularis trends from jejunum to ileum
Jejunum = many plica circularis Ileum = few plica circularis
*remember plica ricularis is associated with absorption
Fat/lymph trends from jejunum to ileum
Jejunum = few fat/lymph Ileum = many fat/lymph
What supplies the jejunum and ileum?
Superior mesenteric artery (midgut)
What quadrants are the jejunum and ileum each respectively found in? What are their relative lengths to each other?
Jejunum = 2/5 found in upper left quadrant
Ileum = 3/5 found in upper right quadrant
Mecke’s (Ileum) Diverticulum is a remnant of ____.
embryonic yolk stalk
What is Mecke’s (ileal) Diverticulum?
- Symptoms?
- Where is it found?
Found ~1m proximal to ileocecal valve (so in ileum)
blind-end tubular outgrowth of the bowel, relatively uncommon
Symptoms: hemorrhage, intussecption, diverticulitis, ulceration, obstruction, appears as fingerlike pouch, symptoms mimic appendicitis
Large intestine _____’s small intestine
Frames
What are the two flexures (both names for each)?
- Right colic flexure aka hepatic flexure
2. Left colic flexure aka splenic flexurew
Right colic flexure is found _____
just inferior to right lobe of liver
aka hepatic flexure
Left colic flexure is found _____
attached to the diaphragm at the splenocolic ligament
Are right colic flexure and left colic flexure symmetrical?
No. But they are both lateral to the ascending/descending segments.
Left colic flexure has more acute bend at junction of transverse and descending, more SUPERIOR and POSTERIOR than right colic.
Which sides of the body are the ascending/descending colons on?
Ascending = right side
Descending = left side
What is the veriform appendix located?
opens into cecum inferior to ileocecal orifice (*lots of variation)
Is the veriform appendix retroperitoneal or intraperitoneal?
Retroperitoneal
Think: it is BEHIND the cecum
What anchors the veriform appendix?
Mesoappendix
Appendicitis symptoms
- vague pain in peri-umbilical region from afferent pain referred to T10 level
- severe pain later from right lower quadrant (from irritation of peritoneum of posterior abdominal wall)
Where is appendicitis pain most severe?
Over the spino-umbilical point
between ASIS and umbilicus
_____ divides the abdominal cavity into supracolic and infracolic.
Transverse mesocolon divides abdominal cavity into supracolic and infracolic
Supracolic components
stomach, liver, spleen
Infracolic components
Small intestine, ascending and descending colon
3 Colon Specializations
- Teniae Coli
- Haustra Coli
- Epiploic Appendages
Teniae Coli definition
Colon specializaton
3 smooth muscle bands paralleling length of colon
Haustra Coli definition
Colon specialization
Outpouching produced by teniae coli
Epiploic appendages definition
Colon specialization
Fat tags along colon
What are the branches of the superior mesenteric artery that supply the small intestine?
- 15-18 intestinal aa
- Ileocecolic a
- Right colic a
- Middle Colic a
- Inferior pancreaticoduodenal (*anastomose with celiac trunk branch)
What does the superior mesenteric artery supply and how is that related to their arterial branches?
Superior mesenteric supplies midgut which is from distal 1/2 duodenum to proximal 2/3 transverse colon
sooo…. 15-18aa, ileocolic (ileum), right colic (ascending), middle colic (transverse), inferior pancreaticoduodenal (duodenum)
What are the branches of the inferior mesenteric artery that supply the small intestine?
- Left Colic
- Sigmoid arteries (4)
- Superior rectal artery
What does the inferior mesenteric artery supply and how is that related to their arterial branches?
Inferior mesenteric artery supplies hindgut which is from distal 1/3 transverse through anal canal.
sooo…. left colic (descending), sigmoid arteries (sigmoid), superior rectal artery (rectum)
Where is the superior mesenteric artery located on the abdominal aorta?
2nd major branch
~1cm inferior to celiac trunk
Where is the inferior mesenteric artery located on the abdominal aorta?
3rd major branch
~5cm superior from aortic bifurcation
What is collateral circulation in the small intestine?
Collateral circulation is achieved by anastomoses between SMA and IMA’s colic branches which creates the…
MARGINAL DRUMMOND
What is the marginal drummond?
connection between middle colic (SMA) and left colic (IMA)
This is an example of collateral circulation of anastomoses between colic branches of IMA/SMA
This helps create superior arch just inferior to transverse crossing both flexures
Where is the superior arch of the colon? How is it created?
Just inferior to transverse colon and crossing both flexures
Created by the marginal drummond (anastomeses between SMA and IMA in colon)
____ and ____ anastomose to supply the head of the pancreas and the duodenum.
Trace back both of the blanks to the abdominal aorta
superior pancreaticoduodenal and inferior pancreaticoduodenal (anterior and posterior both) anastomose to supply the head of the pancreas and the duodenum
superior pancreaticoduodenum comes from gastroduodenal from celiac trunk
inferior pancreaticoduodenum comes from superior mesenteric artery
Pancreas arterial supply is broken down into two components: head region and rest of the pancreas. What supplies each region?
Superior/inferior anterior/posterior pancreaticoduodenal arteries supply head of pancreas and duodenum
Splenic artery supplies the rest of the pancreas with branches
What are the 2 major paired arteries off of the abdominal aorta?
Renal arteries and Gonadal arteries
What is the physical location of the renal arteries coming off of the aorta?
Within 1 inch of SMA on lateral sides of it
Where do the renal arteries enter on the kidney?
Renal arteries enter the hilum on each kidney
Renal artery branches off to supply _______.
Renal artery branches off to supply adrenal glands and ureters
What is the physical location of the gonadal arteries?
Lateral branches of the abdominal aorta inferior to renal arteries
Both gonadal arteries cross over ___.
Both gonadal arteries cross over the ureters
What are the two types of gonadal arteries
Ovarian arteries
Testicular arteries
What is the path of ovarian arteries and where are they going?
Ovarian arteries cross over ureters and iliac vessels
Descends to pelvis to supply ovaries
What is the path of testicular arteries and where are they going?
Testicular arteries cross over ureters and through inguinal canal
Descends into scrotum to supply testes
What is the largest vein in the body?
Inferior vena cava
Where does the IVC begin?
L5 at the union of common iliac veins
IVC returns blood from ______ to RA of the heart.
lower limb, back, abdominal wall, abdominopelvic viscera
What is the portal venous system?
Blood from viscera has to first enter the liver via hepatic vv before entering IVC
What forms the portal vein? Where is it?
The union splenic vein and superior mesenteric vein @ L2
What is the purpose of portal-caval anastomoses?
If damage were to occur, these systems can flow in either direction to maintain blood flow
What allows blood flow in either direction in the portal-caval anastomoses?
Portal veins do not have vales
What are the 4 portal-caval anastomoses?
- Gastric vein (P) and Esophageal vein (C)
- Paraumbilical vein (P) and Epigastric v (C)
- Superior Rectal Vein (P) adn Middle/inferior vein (C)
- Colic vein (P) and Retroperitoneal vein (C)
What is portal hypertension? What does it cause?
increase in blood pressure in portal venous system
RESTRICTS BLOOD FLOW
causes caval vv to be engorged which may cause dilated/varicose veins
What are vericose veins? Where do they occur?
Dilated veins of caval system due to portal hypertension
Vericose occurs because veins not used to being engorged
What are the 3 common locations for caval vein dilation?
- Esophageal Veins
- Epigastric Veins
- Dilated inferior/middle rectal vein
Dilated esophageal veins lead to….
esophageal vericose
Dilated epigastric veins lead to…
Caput medusae (picture of surface anatomy)
around paraumbilical region
Dilated inferior/middle rectum veins leads to….
hemorrhoids
Supply to abdominal viscera is through the ____ Nervous System
Autonomic
Origination of sympathetic nervous system
Thoracolumnar
T5-L2
Origination of parasympathetic nervous system
CNX and S2-4
Craniosacral
Pathway of CX to abdomen
pre-ganglion n from vagus travel on upper arterial branches (celiac trunk, SMA, renal, and all of their branches)
*parasympathetic
Pathway of S2-S4 to abdomen
pre-ganglion n from S2-S4 travel on lower branches (IMA and it’s branches)
Where do synapses occur in parasympathetic innervation?
Synapse occurs with effector organs
Where do synapses occur in sympathetic SPLANCHNIC innervation?
collateral ganglia
Pathway of post-synaptic splanchnic sympathetic nerve fibers?
From collateral ganglia post synpatic sympathetic nerve fibers travel on all main arterial branches (celiac trunk, SMA, renal aa, IMA, and all of their branches)
4 options once pre-synaptic sympathetic nervous fibers enter chain ganglia… what are they?
- Ascend then synapse
- Synapse at level of exit
- Descend then synapse
- Pass through without synapsing so they synapse on the collateral ganglia
What are the 4 main collateral ganglion that sit in the abdomen?
- Celiac ganglion
- Aorticorenal ganglion
- Superior mesenteric ganglion
- Inferior mesenteric ganglion
After collateral ganglion, where do the post-synaptic sympathetic nerve fibers go?
to synapse on the walls of the organs they innervate
What are the 3 thoracic splanchnic nerves?
- Greater splanchnic nerve
- Lesser splanchnic nerve
- Least splanchnic nerve
Greater splanchnic nerve: where does it come from? which collateral ganglion does it synapse on?
Greater splanchnic n (thoracic splanchnic n)
from T5-T9 -> Celiac ganglion
Lesser splanchnic nerve: where does it come from? which collateral ganglion does it synapse on?
Lesser splanchnic n (thoracic splanchnic n)
from T10-T11 -> SMA Ganglion
Least splanchnic nerve: where does it come from? which collateral ganglion does it synapse on?
Least splanchnic n (thoracic splanchnic n)
from T12 -> aorticorenal ganglion
Lumbar Splanchnic nerve: where does it come from? which collateral ganglion does it synapse on?
Lumbar splanchnic n
from L2-L4 -> IMA ganglion
Sacral splanchnics: pathway?
pass through sacral part of sympathetic trunk and enter inferior hypogastric plexus
Pelvic splanchnics: pathway? what does it innervate?
parasympathetics from S2-S4
some fibers pass upwards to inferior abdominal structures innervating distal 1/3 transverse colon, descending colon, sigmoid colon
4 MAJOR AUTONOMIC GANGLION PLEXUSES
- what does it travel along?
- what splanchnic nerves are associated with it?
- Celiac Ganglion
- plexus travels with celiac branches
- CNX and thoracic splanchnics nn - Superior Mesenteric Ganglion
- plexus travels with SMA and branches
- CNX and thoracic splanchnics nn - Aorticorenal Ganglion
- plexus travels with renal branches
- CNX and thoracic suplanchnic nn - Inferior Mesenteric Ganglion
- plexus travels with IMA branches
- Lumbar splanchnic nn and sacral branches
