The Anal Triangle

Question 1

What are the base and apex of the anal triangle?

Answer 1

• The base is the imaginary line between the ischial tuberosities
• The apex is the coccyx

Question 2

When does the rectum become the anal canal?

Answer 2

When it pierces the pelvic floor in the anal triangle

Question 3

What is the name of the spaces either side of the rectum?

Answer 3

Ishiorectal fossae

Question 4

What nerve innervates the external anal sphincter?

Answer 4

The inferior rectal nerve

Question 5

What nerve innervates the wall of the rectum and anal canal?

Answer 5

The inferior rectal nerve

Question 6

What forms the walls of the ishiorectal fossa?

Answer 6

Ischial tuberosity, rectum/anal canal

Question 7

What forms the roof of the ishiorectal fossa?

Answer 7

Levator ani

Question 8

What forms the floor of the ishiorectal fossa?

Answer 8

Skin

Question 9

What forms the contents of the ishiorectal fossa?

Answer 9

Branches of the pudendal nerve, artery, vein and adipose tissue

Question 10

How do the inferior erectile vessels and nerves reach the external anal sphincter?

Answer 10

By crossing the ishiorectal fossa

Question 11

What is the name of the small internal folds in the anal canal?

Answer 11

Anal columns

Question 12

The wall of the anal canal forms the?

Answer 12

Involuntary internal anal sphincter

Question 13

Where is voluntary control of deification from?

Answer 13

The skeletal muscles that surround the opening of the anal canal

Question 14

Where is the external anal sphincter located?

Answer 14

Wraps around the opening of the anal canal and passes between the perineal body and anococcygeal ligament

Question 15

What is the perineal body of the anal canal?

Answer 15

A small dense structure found on the edge of the urogenital diaphragm providing attachment for muscles of the perineum

Question 16

What muscle aids the external anal sphincter by bending the rectum to slow passage of feces?

Answer 16

Puborectalis

Question 17

What vein forms an internal venus rectal plexus that is superficial to the internal sphincter?

Answer 17

Inferior rectal vein

Question 18

What is the pectinate line?

Answer 18

An imaginary line which divides the upper two thirds and lower third of the anal canal

Question 19

What is the anocutaneous line?

Answer 19

Is the transition line between the anal canal to true skin

Question 20

What structures are supplied by the superior rectal artery?

Answer 20

The wall of the rectum (superior area)

Question 21

What structures are supplied by the middle rectal artery?

Answer 21

The middle are of the rectum

Question 22

What structures are supplied by the inferior rectal artery?

Answer 22

The inferior area of the rectum and the anal canal