Infracolic Organs

Question 1

What is haustra?

Answer 1

• balloning of intestine

Question 2

What is the epiploic appendages?

Answer 2

• fat pads on intestine

Question 3

What is mesentery?

Answer 3

• double layer parietal peritoneum of the small intestine that contains fat, blood vessels and nerves

Question 4

What is mesocolon?

Answer 4

• double layer parietal peritoneum of the large intestine that contains fat, blood vessels and nerves

Question 5

Where are the infracolic organs located?

Answer 5

• lie inferior to he transverse colon

Question 6

What is the blood supply to the infraolic organs?

Answer 6

• supplied by the branches of the superior and inferior mesenteric arteries

Question 7

At what vertebral level is the superior mesenteric artery collaterally branch off?

Answer 7

L1

Question 8

At what vertebral level is the inferior mesenteric artery collaterally branch off?

Answer 8

L3

Question 9

What organs does the superior mesenteric arteries supply?

Answer 9

• Jejunum and ileum
• ascending colon
• 1/3 of transverse colon
• hepatic flexure

Question 10

What organs does the inferior mesenteric arteries supply?

Answer 10

• 2/3 of transverse colon
• splenic flexure
• descending colon
• sigmoid colon

Question 11

Where does all the blood from the infracoloic organs drain into?

Answer 11

• the portal vein

Question 12

Is the ascending or descending colon shorter? (and why)

Answer 12

• the ascending colon is shorter due to the liver

Question 13

What is the transverse colon covered in?

Answer 13

• mesocolon

Question 14

In what regions does the jejunum lie?

Answer 14

• umbilical
• left lumbar
• left iliac

Question 15

In what regions does the ileum lie?

Answer 15

• hypogastric
• umbilical
• right iliac
• right lumbar

Question 16

What is the contents of the mesentery?

Answer 16

• branches and tributaries of superio mesenteric artery and vein
• numerous mesenteric lymph nodes and lymphatic vessels
• fat and nerves

Question 17

What sections of the large intestine is in the abdominal region?

Answer 17

• caecum and veriform appendix
• ascending colon
• transverse colon
• descending colon
• sigmoid colon
• left and right colic flexure

Question 18

What sections of the large intestine is in the pelvic and perineal regions?

Answer 18

• sigmoid colon
• rectum
• anal canal

Question 19

How do you locate the caecum on the surface anatomy?

Answer 19

1. draw a line between the umbilicus and right anterior superior iliac spine
2. divide the line into thirds
3. draw a point on 1/3 of the line closet to the right anterior superior iliac spine

Question 20

Why is it important to be able to locate the caecum?

Answer 20

• as it indicates where the base of the appendix attaches for surgery

Question 21

What is the position of the appendix in 64% of people?

Answer 21

• retrocaecal/retrocolic

Question 22

What is the position of the appendix in 32% of people?

Answer 22

• pelvic

Question 23

In which peritoneal space is the ascending colon located?

Answer 23

• retroperitoneal

Question 24

In what percentage of people is the ascending colon have a mesocolon?

Answer 24

• 25%

Question 25

In which peritoneal space is the transverse colon loacted?

Answer 25

- mesocolon

Question 26

What is the average length of the transverse colon?

Answer 26

- 50cm

Question 27

Is the transverse colon not fixed in place? Why/why not?

Answer 27

- no it has much variation (hangs like an apron) due to it being contained in mesecolon instead of attachment with muscles

Question 28

How long is the descending colon?

Answer 28

25cm

Question 29

In which peritoneal space is the descending colon located?

Answer 29

- retoperitoneal

Question 30

In what percentage of people is the descending colon have mesolon?

Answer 30

- 33%

Question 31

What flexure does the descending colon contain?

Answer 31

- splenic/left colic flexure

Question 32

Where is the sigmoid colon located?

Answer 32

- located predominantly in pelvic cavity

Question 33

At what vertebral level does the sigmoid colon terminate?

Answer 33

- S3

Question 34

What is the average length of the sigmoid colon?

Answer 34

- 5 to 80 cm (average 40 cm)

Question 35

Where does the portal vein begin?

Answer 35

- at the confluence between the superior mesenteric vein and the splenic vein

Question 36

What are two main variations of the portal vein?

Answer 36

1. the inferior mesenteric vein is part of the confluence into the portal vein instead of being a tributary to the splenic vein 2. the inferior mesenteric vein becomes a tributary to superior mesenteric vein instead of the splenic vein