Rectum and Anal Canal

Question 1

What is the course of the rectum

Answer 1

It begins as continuation of sigmoid colon in front of third sacral vertebrae and ends slightly below the tip of coccyx

Question 2

What is posterior to the rectum in both males and females

Answer 2

sacrum, coccyx ,

median sacral vessels, Sympathetic chain and sacral plexus

Question 3

What is anterior to the rectum in males

Answer 3

base of urinary bladder,

seminal vesicles, Vas deferens and prostate

Question 4

What is anterior to the rectum in females

Answer 4

posterior vaginal wall

Question 5

What are the muscular folds in the rectum. Which one is temporary, which one is vice versa.

Answer 5

Longitudinal or temporary folds
Transverse or permanent folds
(Houston’s valves)

Question 6

How many valves are in the permanent mucus folds

Answer 6

Four (1st, 2nd, 3rd, 4th)

Question 7

Which valves in the permanent mucus folds are constant and where are they located

Answer 7

First valve (S3) and Third valve (S5)

Question 8

Arterial supply of the rectum

Answer 8

Superior rectal, middle rectal and median sacral artery

Question 9

Venous drainage of the rectum

Answer 9

Superior rectal and middle rectal veins

Question 10

Lymphatic drainage of the rectum

Answer 10

upper part – inferior mesenteric group Lower part – internal iliac nodes

Question 11

Nerve supply of the rectum

Answer 11

Parasympathetic – S2,S3,S4

Sympathetic – L1,L2

Question 12

Where does the anal canal begin

Answer 12

It begins at ano-rectal junction

Question 13

Zones of the interior anal canal

Answer 13

Upper area (pectinate zone)

Intermediate area (pecten)

Lower area (anal verge)

Question 14

What is contained within the upper area of the internal anal canal

Answer 14

Anal columns (columns of morgagni
Anal valves (valves of ball)
Anal papillae
Anal sinuses
Anal glands
Pectinate line

Question 15

What is contained within the intermediate area of the internal anal canal

Answer 15

Extends from Pectinate line to Hinton’s
white line

Lined by non keratinised squamous stratified epithelium

Presence of internal rectal venous plexus

Question 16

What is contained within the lower area of the internal anal canal

Answer 16

Lined by true skin and presence of skin folds

Question 17

Arterial Supply of the anal canal

Answer 17

Superior rectal artery – branch of inferior mesenteric artery

Middle rectal artery – branch of internal iliac artery

Inferior rectal artery – branch of internal pudendal artery (internal iliac artery)

Question 18

Venous drainage of the anal canal above the pectinate line

Answer 18

Internal rectal venous plexus drains into superior rectal vein, which continuous as inferior mesenteric vein
then into portal vein

Question 19

Venous drainage of the anal canal below the pectinate line

Answer 19

External venous plexus drains into inferior rectal vein then into Internal iliac vein then into IVC

Question 20

From which embryologic derivative does above the pectinate line develop

Answer 20

endoderm

Question 21

From which embryologic derivative does below the pectinate line develop

Answer 21

ectoderm

Question 22

Sphincter Ani Internus has which muscles and what kind of movement

Answer 22

Inner circular muscles of rectum and t is iinvoluntary

Question 23

Characteristics of Internal piles or true piles

Answer 23

occurs above pectinate line

They are painless and bleed profusely

Question 24

Characteristics of External piles or false piles

Answer 24

occurs below pectinate line

They are very painful with minimal bleeding