Anatomy 3: Perineum

Question 1

What structures are included in the male perineum?

Answer 1

• External genitalia (urethra, scrotum and penis)
• Perineal muscles
• Anal canal

Question 2

What structures are included in the female perineum?

Answer 2

• Female external genitalia
• Perineal muscles
• Anal canal

Question 3

What perineal triangle lies inferior to pubis symphysis?

Answer 3

Urogenital triangle

Question 4

What perineal triangle lies anteroinferior to the coccyx?

Answer 4

Anal triangle

Question 5

What thin sheet of deep fascia stretches between right and left side of pubic arch below pubic symphysis?

Answer 5

Perineal membrane

Question 6

What innervates external anal sphincter?

Answer 6

Branch of pudendal nerve

Question 7

What is the main actions of external anal sphincter?

Answer 7

• Contrict anal canal during peristalsis

- Support anal floor

Question 8

What innervates bulbospongiosus?

Answer 8

Branch of pudendal nerve, muscular branch of perineal nerve

Question 9

What is the main actions of bulbospongiosus?

Answer 9

• Support pelvic floor
• Male: compress bulb of penis
• Female- assist in clitoris erection

Question 10

What is the innervation of ischiocavernosus?

Answer 10

Branch of pudendal nerve, muscular branch of perineal nerve

Question 11

What is the main actions of ischiocavernosus?

Answer 11

Maintain erection of penis/clitoris

Question 12

What is the innervation of superficial transverse perineal muscle/deep transverse perineal muscle/ext. urethral sphincter?

Answer 12

Branch of pudendal nerve, muscular branch of perineal nerve

Question 13

What is the action of superficial/deep transverse perineal muscle?

Answer 13

• Support perineal body

- Resist increases in intra-abdominal pressure

Question 14

What is the action of external urethral sphincter?

Answer 14

Compress urethra to maintain urinary continence

Question 15

What is the perineal body?

Answer 15

Fibromuscular mass between anus and perineal membrane

Question 16

What is clinical significance of perineal body?

Answer 16

Childbirth can damage it. Leads to prolapse of pelvic viscera

Question 17

What muscles converge towards perineal body?

Answer 17

• Bulbospongiosus
• Ext. anal sphincter
• Levator ani
• Superficial/deep transverse perineal muscles

Question 18

What level of the pelvis is the external urethral sphincter found?

Answer 18

Deep perineal space

Question 19

Is the external urethral sphincter voluntary or involuntary?

Answer 19

Voluntary

Question 20

What level of pelvis is internal urethral sphincter found?

Answer 20

Ischioanal fossa

Question 21

Is the internal urethral sphincter voluntary or involuntary?

Answer 21

Involuntary

Question 22

What are the three parts of the male urethra?

Answer 22

• Prostatic
• Membranous
• Spongy

Question 23

Widest part of urethra? Why?

Answer 23

Prostatic. Transmission of semen

Question 24

Narrowest part of urethra? Why?

Answer 24

Membranous. Voluntary contraction

Question 25

What neurovascular bundle enters the ischioanal fossa through the lesser sciatic foramen?

Answer 25

-Pudental a./v./n.

Question 26

Innervation of ischiocavernosus?

Answer 26

-Branch of pudendal n., muscular branch of perineal n.

Question 27

Action of ischiocavernosus?

Answer 27

Maintain erection

Question 28

Innervation of bulbospongiosus?

Answer 28

Branch of pudendal n.

Question 29

Function of bulbourethral gland?

Answer 29

Secrete mucous during sexual arousal