Lecture 22 DA

Question 1

Branches of which nerve are found within the prostates capsule? What is it responsible for? How is it clinically significant?

Answer 1

Branches of the pudendal nerve, which is responsible for erection in both males and females. It is susceptible in prostatectomy.

Question 2

What is another name for the median and lateral lobes of the prostate?

Answer 2

Median - transition zone

Lateral - Peripheral zone

Question 3

What is a problem with the transition zone with age?

Answer 3

It can be the origin of benign prostatic hyperplasia/hypertrophy, and can encroach on the prostatic urethra, difficult urinating.

Question 4

What is a problem with the peripheral zone?

Answer 4

It is the site of prostatic cancer, which can be imaged.

Question 5

What is the corpus cavernosum? Why is it called cavernosum?

Answer 5

A paired structure within the penis, and is so named as it has lots of space for veins during erection. Veins are compressed and fill with blood.

Question 6

What state is the penis in the anatomical position?

Answer 6

Erect.

Question 7

What is the root of the penis called?

Answer 7

Bulb.

Question 8

What is found at the midline of the penis? What passes through this structure?

Answer 8

Corpus spongiosum, which the urethra passes through. Bordered on both sides by corpus cavernosum.

Question 9

What is the urethra called when within corpus songiosum?

Answer 9

spongy/penile urethra.

Question 10

What is the navicular fossa?

Answer 10

Dilation of the penile urethra at its termination.

Question 11

What is the difficulty with catheter insertion through the urethra in males?

Answer 11

Catheter must navigate a 90° turn from the membranous urethra to the prostatic urethra.

Question 12

What is the prepuce, and what is some pathology regarding HIV associated with it?

Answer 12

Prepuce is the foreskin, and is very sensitive to the HIV virus, and tends to concentrate there. Circumcision helps reduce risk.

Question 13

What are the fascia layers of the scrotum and penile shaft?

Answer 13

Dartos fascia - most superficial (dartos muscle also found).

Deep penile fascia - deep to dartos fascia.

Question 14

Where is the perineum found?

Answer 14

Beneath the pelvic floor, the levator ani.

Question 15

What plane is the urogenital triangle found in?

Answer 15

The horizontal plane, but the anal triangle deviates posteriorly slightly.

Question 16

How are the urethra and vagina angled as they exit the urogenital triangle? What does this form?

Answer 16

They are angled anteriorly as they exit, forming a functional sphincter. Allows for support from above.

Question 17

How is the anal canal angled as it exits the anal triangle?

Answer 17

Angled posteriorly, which forms a sphincteric effect, but is not very capable of resisting forces.

Question 18

What is the cloaca?

Answer 18

Developmentally, the urogenital hole and anal hole are connected as one hole, the cloaca, and seperates later in development.

Question 19

Do birds have a cloaca?

Answer 19

Yes.

Question 20

Is there communication between the urogenital canal and anal canal?

Answer 20

Yes, via perforations.

Question 21

What is the urogenital triangle supported by?

Answer 21

A sheet of fascia and muscle called perineal membrane, which has a mucous membrane on its upper surface.
It also has muscles within the deep perineal pouch, a shallow dish-like space formed by fascia.

Question 22

What is the deep perineal pouch?

Answer 22

A sheet of fascia and muscle. Forms a shallow, dish-like structure with muscles within its space.
The muscles form a sphincter on this sheet.

Question 23

What is sphincter urethrovaginalis?

Answer 23

An additional sphincter in females, which supports the vagina and acts as a sphincter by compressing it.

Question 24

What are the three main components of the urethral sphincter in females?

Answer 24

External urethral sphincter
Compressor urethrae
Urethrovaginal sphincter.

Question 25

Where is the root of the external genitalia and urogenital muscles found?

Answer 25

At the superficial perineal pouch.

Question 26

What is bulbospongiosus?

Answer 26

A skeletal muscle, which contracts to squeeze out all the urine from the urethra after micturition or sperm after ejaculation.

Question 27

What is the perineal body? Is there sexual dimorphism?

Answer 27

A fibrous node, the site of attachment for bulbospongiosus and the anal sphincter. It is bigger in females.

Question 28

How can bulbospongiosus be damaged, and what is a consequence of this?

Answer 28

Pelvic fracture. Urine will accumulate in the extraperitoneal tissue or superficial perineal space, called extravasation.

Question 29

What is extravasation?

Answer 29

When liquid leaks from its container. Happens when bulbospongiosus is damaged.

Question 30

What is the female analogue of the scrotal sac?

Answer 30

Labia majora, found laterally and superficial-most.

Question 31

What is the female analogue of the penile urethra?

Answer 31

Labia minora, found medial to labia majora.

Question 32

Where is the urethra in females?

Answer 32

A urethral opening can be found just inferior to the clitoris. It can open into the vagina posteriorly.

Question 33

What does the urethral opening in females rest on?

Answer 33

Rests on the vestibule, superior to the vagina.

Question 34

What is the hymen, and where is it?

Answer 34

A membrane that partially covers the vaginal opening. It lines the vagina.

Question 35

What kind of muscles are found at the anal termination? What is it supported by?

Answer 35

Smooth muscle. Supported above by puborectalis sling, kinking it.

Question 36

How is the perineal raphe formed?

Answer 36

By the reinforcement of the anus by a deep layer, a superficial layer, and subcutaneous layer, forming a raphe.

Question 37

What innervates the structures of the anus, and where does it come from?

Answer 37

Inferior rectal nerve, which comes from the pudendal nerve and supplies the perineal floor.

Question 38

Which spinal nerves innervate the anus?

Answer 38

S2-4
Useful mneumonic:
S2,3,4 keeps the ass off the floor.

Question 39

How does the pudendal nerve avoid compression from pelvic viscera?

Answer 39

It enters the cavity via the grater sciatic foramen, and exits through the lesser sciatic foramen.