Lower Abdomen Flashcards
Name the major features of the Stomach
Cardiac Orifice
Pyloric sphincter
Rugae
Cardiac Orifice
Entrance to the stomach from the esophagus
Pyloric sphincter
Exit to the duodenum from the stomach
Rugae
Temporary fold in the stomach that have the capability to expand
What are the divisions of the small intestines
Duodenum
Jejunum
Ilium
Plica circularis
Features of the Duodenum, including the divisions
Fixed and relatively immobile 4 divisions (prox. to dist) -Superior part -Descending part -Inferior part -Ascending part
Jejunum
2nd division of the small intestines
Tethered but very mobile
Longer vasa recta, and short, simple aracades
Ilium
Final division of small intestine
Tethered but very mobile
Shorter vasa recta, and more complex arcades
Plica circularis
Permanent folds within the small intestines
Become more diffuse distally
Allow for more surface area
What are the divisions of the large intestines? (prox. to distal)
Cecum Ascending segment Transverse segment Descending segment Sigmoid
What are the 2 flexures of the large intestines and where are they?
Right colic flexure (hepatic) - between ascending colon and transverse colon
Left colic flexure (splenic) - between the transverse colon and descending colon
Tenaie coli
3 longitudinal muscle bands along the length of the colon
Haustra coli
Out-pouching of the colon due to muscle band constriction
Epiploic appendages
Fat tags around the colon
What is a Meckel’s diverticulum?
Remnant of the embryonic yolksac
Appears as a finger-like outpouch tethered to the umbilicus
Located about 1 m proximal to iliocecal calce
If it gets inflamed, it can mirror appendicitis
Veriform appendix
Opens to the cecum inferior to the iliocelcal orifice
Commonly retrocecal, but the orientation varies greatly
Mesoappendix
Small triangular mesentery that helps anchor the appendix
Progression of pain associated with appendicitis
Vague pain begins in periumbilical region around T10 level
Progresses into severe pain in lower right quadrant - from irritation of the peritoneum of the posterior abdominal wall
Pain is most severe over the spinoumbilical point between ASIS and umbilicus
Celiac Trunk
First major branch of the abdominal aorta
Supplies the liver, gallbladder, esophagus, stomach, pancreas, and spleen
3 major branches of the celiac trunk
Common Hepatic
Left Gastric
Splenic
Superior Mesenteric Artery
Second major branch of the abdominal aorta
About 1cm inferior to celiac trunk
Sends 15-18 intestinal arteries to small intestines
Supplies the proximal 2/3 of the transverese colon - via ileocolic, R colic, and middle colic
Has arcades
Arcades
Anastamotic loops of small intestine arterial supply
Ileocolic artery
Branch of SMA
Supplies the Iliocecal junction
R colic artery
Branch of SMA
Supplies ascending colon
Middle colic artery
Branch of SMA
Supplies the proximal 2/3 of the transverse colon
Variations of the SMA and IMA
The pattern of SMA and IMA branching is extremely variable
Anastomoses exist between colic branches for collateral circulation
These form a consistent vasculature around the colon - via the marginal artery of drumond
Arterial anastomoses of the Pancreas
Gastroduodenal artery gives off the Superior Pancreaticoduodenal arteries
SMA gives off Inferior Pancreaticoduodenal artery
-the SPD and IPD anastamoses and supply the duodenum and head of the pancreas
-the splenic artery supplies the rest of the pancreas
Renal arteries
Lateral branches of aorta, lateral to the SMA
Enter the hilum of each kidney to supply it
Send off branches to suprarenal glands and uterus
Suprarenal gland blood supply
Branches from renal arteries, Inferior phrenic artery, and aorta
Gonadal arteries
Lateral branches of abdominal aorta
Come off just inferior to renal arteries
Ovarian arteries and Testicular arteries
Ovarian arteries
Lateral branch of aorta, inferior to renal arteries
Cross over ureters and iliac vessels
Descend to pelvis and supply the ovaries
Testicular arteries
Lateral branch of aorta, inferior to renal arteries
Cross over ureters and enter the inguinal canal
Descend into the scrotum and supply the testicles
Inferior Vena Cava
Largest vein in the body
Begins at L5 level at the union of the common iliac vein
Inferior Vena Cava drainage
Drains the lower left, most of the back, abdominal wall, and abdominopelvic viscera to Right atrium of the heart
Portal Vein
Formed by the union of the Splenic and Superior Mesenteric Veins (at L2 level)
Portal Vein drainage
Return from spleen, pancreas, gallbladder and GI tract to the IVC
Gastric vein anastomoses with…
Esophageal vein
Paraumbilical vein anastomoses with…
Epigastric veins
Superior rectal vein anastomoses with…
Middle/Inferior Rectal vein
Colic veins anastomoses with…
Retroperitoneal vein
Describe the portal-caval anastomoses
Portal venous system has no valves, so reversal of blood flow is possible.
Portal hypertension restricts bloodflow, causing caval veins to be engorged and dilated - potentially causing vascular rupture and hemorrhaging
Dilated esophageal vein produces…
Esophageal varicose veins
Dilated Epigastric veins produce…
Caput medusae
Dilated Inf. and Mid. Rectal veins produce…
Hemorrhoids
Where do the sympathetic fibers of the abdomen originate?
T5-L2/3 - Thoracocolumbar plexus
Where do the parasympathetic fibers of the abdomen originate?
CN X and S2-4 - Craniosaral plexus
Where do preganglionic sympathetic splanchnic nerves of the abdomen synapse?
Collateral ganglia
Where do postsynaptic sympathetic fibers of the abdomen travel?
All major arterial branches, and supply the organ that the branches they travel with supply.
Where do preganglionic nerves from CNX travel?
On upper abdominal arterial branches - Celiac trunk, SMA, renal arteries, and their branches
Supply the same organs as the arteries they run with
Where do preganglionic nerves from S2-S4 travel?
On lower abdominal arterial branches - IMA and its branhces
Supply the same organs as the arteries they run with
Where do pregangionic sympathetic fibers of the abdomen synapse?
Within their effector organs
Describe the Celiac ganglion
Plexuses travel with celiac trunk branches
Receive thoracic splanchnic nerves and CN X
Describe the Superior Mesenteric ganglion
Plexuses travel with SMA branches
Receive thoracic splanchnic nerves and CN X branches
Describe the Aorticorenal ganglion
Plexuses travel with renal branches
Receive thoracic splanchnic nerves and CN X branches
Describe the Inferior Mesenteric ganglion
Plexuses travel with IMA branches
Receive lumbar splanchnic nerves and S2-S4 branches
