Perineum

Question 1

Which structure runs through the corpus cavernosum in the penis?

Answer 1

central artery

Question 2

What allows a male to maintain an erection?

Answer 2

The central arteries in the corpus cavernosum open completely and allow blood through. The blood enters faster than it can leave through the veins, thus trapping blood in the penis. As the penis swells, it further blocks venous return and allows erection to be maintained.

Question 3

Which erectile tissue contributes to the formation of the clitoris?

Answer 3

corpus cavernosum only

Question 4

Which erectile tissue contributes to the formation of the penis?

Answer 4

corpus cavernosum and corpus spongiosum

Question 5

Which is more deep in the penis– the corpus cavernosa or corpus spongiosum?

Answer 5

corpus spongiosum

Question 6

In females, are the vestibular glands in the superficial or deep pouch?

Answer 6

superficial pouch

Question 7

In males, are the bulbourethral glands in the superficial or deep pouch?

Answer 7

deep pouch

Question 8

Which muscle lies over the corpus cavernosa tissue?

Answer 8

ischiocavernosus muscle

Question 9

Which muscle lies over the corpus spongiosum tissue?

Answer 9

bulbospongiosus muscle

Question 10

Which muscle extends transversely from the ischial tuberosities to the perineal body?

Answer 10

superficial transverse perineus

Question 11

What is another name for the inferior fascia of the UG diaphragm? Is it thick or thin?

Answer 11

perineal membrane; it is very thick (can actually feel it)

Question 12

What are the two muscles found in the deep pouch of the perineum?

Answer 12

• sphincter urethrae

- deep transverse perineus

Question 13

What forms the Alcock’s (pudendal) canal?

Answer 13

fascia of the obturator internus muscle

Question 14

What is contained within the Alcock’s canal?

Answer 14

• internal pudendal artery and veins

- pudendal nerve

Question 15

What are the main branches of the pudendal nerve that we discussed?

Answer 15

• perineal nerve

- inferior rectal nerve

Question 16

What is the function of the ischiocavernosus in males vs. females?

Answer 16

• males: helps maintain erection

- females: helps tense the vagina during orgasm

Question 17

What is the most common site of tear in the straddle injury?

Answer 17

membranous part of the urethra (because it is the narrowest part)

Question 18

There is a gap between the _____ and ______ in a straddle injury.

Answer 18

rectus sheath; scarpa’s (Colle’s) fascia

Question 19

_____ fascia turns into _____ fascia in the perineum.

Answer 19

Scarpa’s; Colle’s

Question 20

What innervates the anal canal?

Answer 20

• autonomic inn. from inferior hypogastric plexus

- somatic inn. from inferior rectal n.

Question 21

Why is the pectinate (dentate) line an important landmark?

Answer 21

It separates the visceral and parietal components of the anal canal and separates where internal vs. external hemorrhoids would be found. Above the pectinate line is GVA/GVE, and below the pectinate line is GSA /GSE.

Question 22

What is the urogenital diaphragm?

Answer 22

It corresponds to the deep pouch of the perineum. It includes the deep transverse perineal muscle and sphincter urethrae, as well as the Cowper’s glands (in males).

Question 23

What is contained within the superficial pouch?

Answer 23

• Erectile tissue (corpora cavernosa and spongiosa)
• Ischiocavernosus muscle
• Bulbospongiosus muscle
• Superficial transverse perineal muscle
• Vestibular glands (females only)

Question 24

What is contained within the deep pouch?

Answer 24

• Deep transverse perineal muscle
• Sphincter urethrae muscle
• Cowper’s glands (males only)