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Flashcards in Chapter 12 Deck (55):
1

What is the main purpose of the colon?

Absorption of water and sodium

2

Tx of uncomplicated diverticulitis

IV abx and bowel rest
If complicated and/or recurrent: elective colectomy

3

What is the leading cause of LBO?

Cancer

4

Tx for ulcerative colitis

Can do total protocolectomy with end end ileostomy or total protocolectomy with ileal pouch and anastamosis

5

What is the most common form of intestinal volvulus?

Sigmoid volvulus

6

Tx of sigmoid volvulus

Detorsion via sigmoidoscopy followed by bowel prep and elective sigmoidoscopy with primary anastamosis or Hartmann's procedure

7

What is the initial tx for anal squamous cell carcinoma?

Chemoradiation

8

What are the most common tumors of the appendix?

Carcinoid tumors

9

Where is the foregut? What is it supplied by?

End at 2nd portion of the duodenum
Supplied by the celiac artery

10

Where is the midgut?
What is it supplied by?

Duodenal ampulla to the 1st 2/3 of the transverse colon
Supplied by the SMA

11

Where is the hindgut?
What is it supplied by?

Distal transverse and descending colon as well as proximal rectum
Supplied by IMA

12

What supplies the distal rectum?

Internal iliac artery

13

How is the anus formed?

By an invagination of the ectomdermal anal pit and fuses with the distal rectum at the dentate line

14

What are the four major layers of the colon?

Mucosa (columnar epithelium)
Submucosa (muscularis mucosa)
Muscularis propria
Serosa

15

Muscularis propria

Inner circular
Outer longitudinal smooth muscle: forms three bands
-Teniae coli (run along the colon and converge distally at the top of the rectum)
-Produce haustra, which give the colon its appearance on X-ray

16

How long is the colon?

150 cm

17

Where does the colon start and end?

Starts at the cecum in the RLQ
Ends 15 cm from anal verge

18

How long is the rectum?

12-15 cm long

19

Where does the rectum start and end?

Peritoneal reflection to the dentate line (2-4 cm from anal verge)

20

What is the most common site of rupture secondary to obstruction or pseudo-obstruction?

Cecum

21

What is the average diameter of the cecum?

7.5 cm
Most capacious area of the colon

22

Where is the appendix?

Arises from base of cecum-within 2-3 cm of ileocecal valve

23

What is the MC position of the appendix tip?

Posterior to the cecum

24

Position of the right colon

Posterior surface is retroperitoneal and lies near the duodenum

25

Position of transverse colon
What is it suspended by?

Completely intraperitoneal
Suspended by broad mesentery

26

Which flexure is higher than the other?

Splenic flexure is higher than the hepatic flexure

27

Greater omentum

Gastrocolic ligament (coming from greater curve of the stomach) fuses to peritoneal covering of the colon

28

Position of the descending colon

Partially retroperitoneal and fixed

29

Position of the sigmoid colon

Intraperitoneal

30

How is the upper 1/3 of the rectum covered?

Anteriorly and laterally by peritoneum

31

How is the middle 1/3 of the rectum covered?

By peritoneum anteriorly

32

Position of the distal rectum

Entirely extra-peritoneal

33

How is the posterior rectum covered?

By fascia propria

34

What preserves the lymphatics during rectal cancer surgery?

Dissecting in the plan between the fascia propria of the rectum and sacrum

35

How many rectal ligaments are formed by the fascia propria?
What do they contain?

2
Middle rectal artery and mixed autonomic nerves

36

If the mixed autonomic nerves in the two rectal ligaments of the fascia propria get injured, what can result?

Erectile of bladder dysfunction

37

Where does the anus begin?

At dentate line
Surgically begins at the level of the pelvic floor muscle

38

What do the mucosa at the dentate line form?

Longitudinal folds called columns of Morgagni

39

If the bases of the columns of Morgagni are infected, what is the result?

Anorectal abscesses and fistulas

40

How is fecal continence controlled?

By muscles of the pelvic floor

41

What are the muscles of the pelvic floor that control fecal continence called?

Levator ani
Internal anal sphincter (involuntary smooth muscle)
External anal sphincter (striated voluntary muscle)

42

What supplies the right colon and first 2/3 of transverse via its branches (middle, right, and ileocolic)?

The SMA via the aorta

43

Where does the ileocolic branch of the SMA go to?

Appendiceal artery

44

What is the blood supply of the proximal and middle thirds of the transverse colon?

The middle colic artery branch of the SMA which branches off into left and right branches

45

What is usually ligated during a right colectomy?

Right branch of the middle colic branch of the SMA

46

What supplies the left colon and proximal rectum?

The IMA via the aorta, which branches into the left colic, sigmoidal, and superior rectal vessels

47

What supplies the distal rectum and anus?

The middle rectal artery via the internal iliac AND
the inferior rectal artery via the internal pudendal artery

48

Marginal artery of Drummond

Series of arterial arcades running along the mesenteric border of the entire colon

49

Arc of Rioland

Connects proximal SMA and IMA

50

What is at risk for ischemia because it lies between the SMA and IMA?

Splenic flexure

51

Venous drainage

IMV leads to splenic vein, joins with SMV to form the portal vein
Distal rectum and anus drained by the middle and inferior rectal veins, goes to internal iliac veins, goes to systemic circulation

52

Lymphatics

Follows blood supply
Tumor in mid/distal rectum goes to iliac nodal basins

53

Sympathetic innervation

Runs along blood vessels
Thoracic roots supply SMA distribution
Lumbar roots supply IMA distribution
Sacral roots supply tpelvic floor, distal rectum and anus

54

When can occur if the hypogastric nerve is injured when ligating the IMA?

Ejaculatory dysfunction

55

Parasympathetic innervation

Right vagus innervates the right and transverse colon
Sacral roots innervate left colon and rectum