Infracolic Organs Flashcards
What is haustra?
- balloning of intestine
What is the epiploic appendages?
- fat pads on intestine
What is mesentery?
- double layer parietal peritoneum of the small intestine that contains fat, blood vessels and nerves
What is mesocolon?
- double layer parietal peritoneum of the large intestine that contains fat, blood vessels and nerves
Where are the infracolic organs located?
- lie inferior to he transverse colon
What is the blood supply to the infraolic organs?
- supplied by the branches of the superior and inferior mesenteric arteries
At what vertebral level is the superior mesenteric artery collaterally branch off?
L1
At what vertebral level is the inferior mesenteric artery collaterally branch off?
L3
What organs does the superior mesenteric arteries supply?
- Jejunum and ileum
- ascending colon
- 1/3 of transverse colon
- hepatic flexure
What organs does the inferior mesenteric arteries supply?
- 2/3 of transverse colon
- splenic flexure
- descending colon
- sigmoid colon
Where does all the blood from the infracoloic organs drain into?
- the portal vein
Is the ascending or descending colon shorter? (and why)
- the ascending colon is shorter due to the liver
What is the transverse colon covered in?
- mesocolon
In what regions does the jejunum lie?
- umbilical
- left lumbar
- left iliac
In what regions does the ileum lie?
- hypogastric
- umbilical
- right iliac
- right lumbar
What is the contents of the mesentery?
- branches and tributaries of superio mesenteric artery and vein
- numerous mesenteric lymph nodes and lymphatic vessels
- fat and nerves
What sections of the large intestine is in the abdominal region?
- caecum and veriform appendix
- ascending colon
- transverse colon
- descending colon
- sigmoid colon
- left and right colic flexure
What sections of the large intestine is in the pelvic and perineal regions?
- sigmoid colon
- rectum
- anal canal
How do you locate the caecum on the surface anatomy?
- draw a line between the umbilicus and right anterior superior iliac spine
- divide the line into thirds
- draw a point on 1/3 of the line closet to the right anterior superior iliac spine
Why is it important to be able to locate the caecum?
- as it indicates where the base of the appendix attaches for surgery
What is the position of the appendix in 64% of people?
- retrocaecal/retrocolic
What is the position of the appendix in 32% of people?
- pelvic
In which peritoneal space is the ascending colon located?
- retroperitoneal
In what percentage of people is the ascending colon have a mesocolon?
- 25%
In which peritoneal space is the transverse colon loacted?
- mesocolon
What is the average length of the transverse colon?
- 50cm
Is the transverse colon not fixed in place? Why/why not?
- no it has much variation (hangs like an apron) due to it being contained in mesecolon instead of attachment with muscles
How long is the descending colon?
25cm
In which peritoneal space is the descending colon located?
- retoperitoneal
In what percentage of people is the descending colon have mesolon?
- 33%
What flexure does the descending colon contain?
- splenic/left colic flexure
Where is the sigmoid colon located?
- located predominantly in pelvic cavity
At what vertebral level does the sigmoid colon terminate?
- S3
What is the average length of the sigmoid colon?
- 5 to 80 cm (average 40 cm)
Where does the portal vein begin?
- at the confluence between the superior mesenteric vein and the splenic vein
What are two main variations of the portal vein?
- the inferior mesenteric vein is part of the confluence into the portal vein instead of being a tributary to the splenic vein
- the inferior mesenteric vein becomes a tributary to superior mesenteric vein instead of the splenic vein
