Pelvis And Perineum 2

Question 1

Describe the anatomy of Testes

Answer 1

Two ovoid shaped organs that develop in the abdominal cavity and descend into the scrotum

Takes its blood supply and venous drainage with it
Sites of sperm production throughout the adult life starting in puberty

Located in the scrotum to allow for careful temperature regulation

Still considered internal organs since the blood supply, lymphatic drainage and innervation are all derived from the lumbar region

Question 2

Describe the anatomy of the ductus deferens

Answer 2

Muscular tube originating from the tail of the epididymis

Passes in the spermatic cord through the inguinal canal towards the posterior aspect of the bladder

It expands to form the ampulla before joining the duct of the seminal vesicle to form the ejaculatory duct

Question 3

What are the seminal vesicles?

Answer 3

Paired glands
posterior to bladder
Duct joins ampulla of ductus deferens to form ejaculatory duct
Produces about 60% of volume of semen

Question 4

Describe the anatomy of the prostate gland

Answer 4

• Almond shaped gland in the prepubescent individual that gradually increase in size with age under the influence of DHT-5
• Base - at bladder neck
• Apex - at UG hiatus of pelvic diaphragm in contact with the superior fascia of the deep perineal pouch
• Posterior aspect lies in close relation to the ampulla of the rectum
• The ejaculatory ducts pass through it to drain into the urethra

Question 5

Contrast the types of prostatic divisions

Answer 5

Anatomical lobes
These divisions are based on where the different parts can be palpated
The median lobe is anterior to the ejaculatory ducts while the posterior lobe is posterior, both these lobes are posterior to the urethra

Anatomical zones
The regions of the prostate based on the histological structure
These zones are also related to the different disease processes that may affect

Question 6

Explain what is a digital rectal exam

Answer 6

Digital rectal exam is important for detection of prostate abnormalities. DRE in combination with Prostate Specific Antigen (PSA) will help determine the possibility of prostate cancer and benign prostatic hyperplasia

Structures that can be palpated in the male are : prostate, seminal vesicle, rectovesical pouch

Structures that can be palpated in the female are: posterior wall of vagina, cervix, rectouterine pouch (of Douglas)

Question 7

What is benign prostatic hyperplasia?

Answer 7

• Hyperplasia of the glandular epithelium
• Transitional and periurethral zones
• Due to the location of the hyperplasia it causes urethral obstruction
• On DRE the prostate feels bulky

Question 8

What is prostate cancer?

Answer 8

• Most commonly diagnosed cancer in men
• Peripheral zone
• Relatively asymptomatic
• On DRE the prostate feels hard like a rock

Question 9

When is transurethral resection of prostate(TURP)?

Answer 9

Done for BPH due to location of enlarged tissue

Question 10

What is the blood supply to the male perineum?

Answer 10

Inferior vesicle artery: bladder neck and prostate

Vesical and prostatic venous plexuses: drain mainly to iliac veins but also communicate with the external vertebral venous plexus

Communicates with the internal vertebral plexus (of Batson) valveless system

Question 11

What is the significance of prostatic cancer metastasis ?

Answer 11

Since the prostatic plexus and the internal venous plexus of veins have a communication, cancer cells may spread via this route.
This plexus connects specifically to the venous drainage of the cranial cavity and may serve as a route for metastasis to the brain.

Question 12

Summarize lymphatic drainage of the male perineum

Answer 12

Testes drain to lumbar nodes

Prostate, seminal vesicles, ductus deferens drain into internal iliac nodes

Question 13

What is the urogenital triangle?

Answer 13

The crura are covered by the ischiocavernosus muscles

The bulbospongiosus muscle covers the bulb of the penis and the two sides fuse together to form a raphe

Contraction of these two muscles assist in expulsion of semen from the urethra during ejaculation

Question 14

What are the roles of which external genitalia for the male?

Answer 14

Suspensory ligament of the penis
extends from the pubic symphysis to the the dorsal aspect of the body of the penis

Prepuce/ foreskin
surrounds the glans, is the part removed during circumcision

Bulb
covered by bulbospongiosus muscles

Scrotum
Skin and fascia that contains the testes

Question 15

What is the role of the corpus cavernosum?

Answer 15

Crura that lie lateral to the corpus spongiosum

Question 16

What is the root of the penis?

Answer 16

Anatomical position is erect The penis has a root consisting of
both the crura and the bulb
The crura consist of corpus cavernosum, erectile tissue with large spaces

Question 17

What is the anatomy of the corpus spongioum?

Answer 17

The corpus spongiosum has smaller spaces and contains the urethra along its entire length

The glans is an expansion of the spongiosum into which the two corpora cavernosa fit

The ridge formed by the glans is known as the corona

Question 18

What is the glans penis?

Answer 18

Expanded portion of the corpus spongiosum

Question 19

What is the bulb of the penis?

Answer 19

Expanded proximal portion of corpus spongiosum

Question 20

Summarize the penis internal structure

Answer 20

The erectile tissue remain as three distinct bodies
The erectile bodies are surrounded by a thick fibrous fascia = tunica albuginea, septa divide the cavernosum into cavernous spaces into which the helicine arteries open
The Buck’s Fascia encloses all three bodies

Question 21

What is the navicular fossa?

Answer 21

Expanded portion of the spongy urethra

Question 22

Clinically the urethra is divided into

Answer 22

Anterior and posterior portions

Question 23

What is anterior urethral injury?

Answer 23

Injury to the urethra is common in straddle injuries such as; falling on a bicycle crossbar, fence or any hard surface with open legs
This will cause urine (and blood) to leak out into the surrounding tissues
Since Buck’s fascia is fibrous the injury may not tear into it

No injury to Buck’s fascia Extravasation is limited to the penis (deep to Buck’s)

With injury to Buck’s fascia Extravasation will extend into the superficial perineal pouch

Question 24

What can cause a posterior urethral tear?

Answer 24

May be due to straddle injuries or direct trauma to the groin. Symptoms may include blood leaking from the urethral orifice and pain.

Question 25

Describe the terminal portion of internal pudendal artery

Answer 25

Terminal portion of internal pudendal a. accompanies the dorsal nerve of the penis: supplies the deep perineal pouch and erectile tissues

Males: artery of the bulb of the penis, urethral artery, deep artery of the penis and dorsal artery of the penis

Question 26

Describe autonomic innervation of male perineum

Answer 26

Parasympathetic fibers from the pelvic splanchnic nerves (S2-4) to the erectile tissues travel via the prostatic plexus and run to the erectile tissues as the cavernous nerves these cause dilation of helicine arteries allowing filling of blood for erection

hypogastric nerves bring sympathetic fibers

pelvic splanchnic nerves add PNS fibers

sacral splanchnic nerves add SNS fibers

Question 27

Describe the nervous importance of erection

Answer 27

• Parasympathetic innervation by the cavernous nerves causes dilation of the arteries to the penis, clitoris and bulbs of the vestibule
• This causes the vascular spaces inside the erectile tissues to fill with blood
• Due to the resulting enlargement of the corpora cavernosa the veins are compressed preventing the blood from draining temporarily

Since erection is a vascular event prolonged erection is extremely dangerous; a condition known as priapism

Interruption of the cavernous nerves during prostatectomy leads to erectile disfunction

Question 28

Describe the science behind the emission phase of the ejaculation

Answer 28

Emission phase:
Sympathetic innervation
promotes secretion of fluids by the glands and smooth muscle contractions of the ductus deferens and ejaculatory ducts
causing semen to accumulate in the urethral bulb = inferior hypogastric plexus

Internal urethral sphincter contracts closing the communication to the bladder

Question 29

Describe the expulsion of the ejaculation phase

Answer 29

Expulsion phase:
Rhythmic contractions of the bulbospongiosus and ischiocavernosus muscles = pudendal nerve
• Expels semen accumulated during the emission phase through the urethra
• simultaneous sympathetic innervation causes constriction of vessels and reduces erection