Anal Triangle

Question 1

What makes up the walls of the ischioanal fossa?

Answer 1

• Ischial tuberosity
• Rectum/anal canal

Question 2

What makes up the roof of the ischioanal fossa?

Answer 2

Levator ani

Question 3

What makes up the floor of the ischioanal canal?

Answer 3

Skin

Question 4

What are the contents of the ischioanal canal?

Answer 4

• Branches of pudendal nerve
• Branches of pudendal artery/vein
• Adipose tissue

Question 5

Identify the features of the anal canal.

Answer 5

Question 6

What part of the anal canal is smooth muscle?

Answer 6

Internal anal sphincter

Question 7

What part of the anal canal is skeletal muscle

Answer 7

External anal sphincter

Question 8

At what point does the rectum become the anal canal?

Answer 8

When it pierces the pelvic floor

Question 9

What do the anal columns contain?

Answer 9

• Terminal radicle of the superior rectal vessels
• Anal sinus related

Question 10

What type of muscle is present at the external anal sphincter?

Answer 10

Skeletal muscle

Question 11

Where is the external anal sphincter located?

Answer 11

From perineal body to anococcygeal ligament.

Question 12

What is the function of the external anal sphincter?

Answer 12

Closes the anus

Question 13

What aids rectal control along side the external anal sphincter?

Answer 13

Puborectalis muscle

Question 14

What innervates the external anal canal?

Answer 14

Inferior rectal branch of the pudendal nerve (S2-4)

Question 15

What happens at the pectinate line?

Answer 15

End of the visceral internal part of the digestive tract

Question 16

What happens at the anocutaneous line?

Answer 16

Transition to true skin

Question 17

Describe the arterial supply of the anal canal.

Answer 17

• Superior rectal artery
• Middle rectal artery
• Internal pudendal artery
• Inferior rectal artery

Question 18

What artery gives branches to supply the anal canal above the pectinate line?

Answer 18

Inferior mesenteric artery

Question 19

What vein does blood drain to above the pectinate line?

Answer 19

Portal venous system

Question 20

What artery gives branches to supply the anal canal below the pectinate line?

Answer 20

Internal iliac artery

Question 21

What vein does blood drain to below the pectinate line?

Answer 21

Caval venous system

Question 22

Where does lymph drain above the pectinate line?

Answer 22

Internal iliac nodes

Question 23

Where does lymph drain to below the pectinate line?

Answer 23

Superficial inguinal nodes

Question 24

Describe the innervation above the pectinate line.

Answer 24

• Visceral motor
• Mixed sympathetic and parasympathetic
• Sensory innervation

Question 25

Describe the innervation below the pectinate line.

Answer 25

• Somatic motor
• Sensory innervation