Colorectal

Question 1

macroscopic features of colon

Answer 1

eva has ten socks
e - epiploic appendages
h - haustra
t - taeniae coli
s - semilunar folds

Question 2

blood supply to ascending and transverse colon

Answer 2

branches of superior mesenteric artery
- right colic artery, ileocolic artery

Question 3

blood supply to descending and sigmoid colon

Answer 3

inferior mesenteric artery
- left colic and sigmoid arteries

Question 4

which arteries form anastamosis of riolan and where does blood drain

Answer 4

middle and left colic arteries
drains into superior and inferior mesenteric veins

Question 5

innervation up to left colic flexure and name of point

Answer 5

up to cannon boehm point
sympathetic - superior mesenteric plexus
parasympathetic - vagus

Question 6

after cannon boehm point innervation

Answer 6

sympathetic - inferior mesenteric plexus
parasympathetic - pelvic splanchnic nerves

Question 7

parts of taenia coli

Answer 7

mesocolic
omental
free

Question 8

2 junctions in rectum

Answer 8

rectosigmoidal
anorectal

Question 9

name the flexures in the rectum (2)

Answer 9

vertical
- Sacral
- Perineal
lateral
- Superior
- Intermediate
- Inferior lateral

Question 10

3 zones of anal canal

Answer 10

columna - intraperitoneal
intermediate - retroperitoneal
cutaneous - extraperitoneal

Question 11

features of columna

Answer 11

folded mucous membrane creating columnar folds
connected distally by anal valves
cavity behind valves where the excretory ducts of the anal glands open into

Question 12

2 anal sphincters

Answer 12

internal
- upper 2/3s
- smooth muscle permanently contracted by sympathetic and only relaxes in para influence
o External
Lower 2/3 anal canal
Voluntary control

Question 13

main 3 arteries providing blood supply to rectum and anal canal and which parts do they supply

Answer 13

superior rectal = majority of rectum and anal canal above pectinate line
middle rectal - middle rectum and whole anal canal
inferior rectal - distal rectum and anal canal below pectinate line

Question 14

where does superior rectal artery come from

Answer 14

inferior mesenteric artery

Question 15

where does middle rectal artery originate

Answer 15

internal iliac

Question 16

where does inferior rectal artery originate from

Answer 16

internal pudendal

Question 17

3 rectal venous plexuses

Answer 17

internal
external- (inferior rectal veins) within muscular wall
perimuscular - external to muscular wall

Question 18

where do the rectal veins drain to

Answer 18

superior - portal venous system via inferior mesenteric vein
middle - internal iliac
inferior - internal pudendal

Question 19

innervation of rectum

Answer 19

sympathetic - lumbar splanchnic nerves, superior hypogastric plexus and inferior hypogastric plexus
parasympathetic - pelvic splanchnic and inferior hypogastric plexus

Question 20

innervation of anal canal above pectinate line

Answer 20

• Inferior mesenteric plexus
• Pelvic splanchnic nerves
• Inferior hypogastric plexus

Question 21

innervation of anal canal below pectinate line

Answer 21

pudendal

Question 22

internal and external haemorrhoids

Answer 22

internal
dilation of the internal venous plexus
painless and may only be indicated by bleeding.
external
dilation or thrombosis of the external venous plexus
more painful
can cause region to necrose - gangrene

Question 23

associated muscles and structures

Answer 23

levator ani (pelvic floor)
ischioanal fossa (inferior to lavator ani)
pudendal canal

iliacus muscle
ilipsoas muscle
obturator internus (hip)