Perineum and its pouches

Question 1

Boundaries of the perineum

Answer 1

Anteriorly - pubic symphysis
Anterolaterally- inferior pubic and ischial rami
Laterally- Ischial tuberosities
Posterolaterally- Sacrotuberous ligaments
POSteriorly- Inferiormost sacrum and coccyx

Question 2

What are the two triangles of the perineum and what divides them

Answer 2

Transverse line joining anterior ends of ischial tuberosities divides perineum into:

• ANal triangle
• Urogenital triangle

Question 3

What is the superficial perineal pouch

Answer 3

A potential space between the membranous layer of subcutaneous tissue and the perineal membrane bounded laterally by ischiopubic rami

Question 4

What doe the superficial perineal pouch contain in males

Answer 4

Root of penis and ischiocavernosus and bulbospongiosus

Proximal part of the spongy urethra

Superficial transverse perineal muscles

Deep perineal branches of the internal pudendal vessels and pudendal nerves

Question 5

What does the superficial perineal pouch contain in females

Answer 5

Clitoris and ischiocavernosus

Bulbs of the vestibule and surrounding muscle (bulbospongiosus)

Greater vestibular glands

Deep perineal branches of the internal pudendal vessels and pudendal nerves

Superficial transverse perineal muscles

Question 6

Boundaries of the ischioanal fossa

Answer 6

Laterally- ischium and inferior part of obturator internus

Medially- anal sphincter, with a sloping superior medial wall or roof formed by levator ani

Posteriorly- sacrotuberous ligament and gluteus Maximus

Anteriorly- bodies of the pubic bones

Question 7

Contents of iscioanal fossa

Answer 7

Perineal branch of S4

Inferior anal/rectal vessels and nerves

Perforating branch of S2 and S3

Question 8

Structures which run through the pudendal canal

Answer 8

Internal pudendal artery and vein

Pudendal nerve

Nerve to the obturator interns

these all enter the canal at the lesser sciatic notch

Question 9

What do the internal pudendal vessels supply and drain

Answer 9

Perineum

Question 10

What does pudendal nerve split into

Answer 10

Inferior anal/rectal nerve

Perineal nerve: muscular (deep) branches and superficial branch
–>Superficial branches divide to form posterior scrotal nerves

Dorsal nerve of penis

Question 11

What are the primary sensory nerves serving the male or female organ

Answer 11

Dorsal nerve of the penis or clitoris

Question 12

What does the ductus deferens enlarge to form before its termination

Answer 12

Ampulla of ductus deferens

Question 13

What does the ductus deferens narrow and join the duct of and what does it form

Answer 13

Duct of seminal gland to form the ejaculatory gland

Question 14

What does the fibrous capsule of the prostate contain

Answer 14

Prostatic plexuses of nerves and veins

Question 15

Where is the isthmus of the prostate and where does it lie

Answer 15

lies anterior to the urethra

Question 16

What are the different lobes of the prostate

Answer 16

Right and left lobe of the prostate:

• Inferoposterior lobule
• Inferolateral lobule
• Superomedial lobule
• Anteromedial lobule

Question 17

What are prostatic arteries branches of

Answer 17

Internal iliac artery

Question 18

What do the prostatic veins join to form

Answer 18

Prostatic venous plexus

Question 19

What is the base of the prostate related to

Answer 19

Closely related to neck of bladder

Question 20

What is the apex of the prostate in contact with

Answer 20

Fascia on the superior aspect of the urethral sphincter and deep perineal muscles

Question 21

What is the posterior surface of the prostate related to

Answer 21

Ampulla of the rectum

Question 22

What are the inferolateral surfaces of the prostate related to

Answer 22

Levator ani

Question 23

What do the lymph vessels of the prostate drain into

Answer 23

Internal iliac nodes but some pass to the sacral lymph nodes

Question 24

What is the perineal body

Answer 24

Central tendon of perineum. It is a pyramidal fibromuscular mass in the middle line of the perineum at the junction between the urogenital triangle and the anal triangle

Question 25

What are the structures related to the perineal body

Answer 25

ISchiocavernosus
Bulbocavernosus
Transverse perineal

Question 26

Where does the spermatic cord begin and end

Answer 26

Begin- inferior abdomen

End-Scrotum

Question 27

Where is the spermatic cord formed at

Answer 27

Opening of the inguinal canal (deep inguinal ring)

opening is located lateraly to the inferior epigastric vessels

Question 28

How does the spermatic cord enter the scrotum

Answer 28

Superficial inguinal ring

Question 29

What are the contents of the spermatic cord bound together by and where are these derived from

Answer 29

3 fascial layers which are derived from the anterior abdominal wall

Question 30

What are the fascial layers which bind the contents of the spermatic cord together and what are they derived from

Answer 30

External spermatic fascia
–> derived from deep subcutaneous fascia

Cremaster muscle and fascia
–> derived from the internal oblique muscle and its fascial coverings

Internal spermatic fascia
–>Derived from the transversalis fascia

Question 31

What is the cremasteric reflex

Answer 31

Stimulated by stroking the superior and medial part of the thigh. Produces an immediate contraction of the cremaster muscle which elevates the testis on the side that has been stimulated

Question 32

What are the two parts of the cremasteric reflex

Answer 32

Afferent (sensory) limb - ilioinguinal nerve (innervates the skin of the superomedial thigh). fibres from this nerve enter the spinal cord at L1

Efferent (motor) limb -genital branch of the genitofemoral nerve (innervates the cremaster muscle)

Question 33

Blood vessels in the spermatic cord and what they do

Answer 33

Testicular artery - branch of the aorta that arises just inferiorly to the renal arteries

Cremasteric artery and vein- suppplie the cremasteric fascia and muscle

Artery to the vas deferens- branch of the inferior vesicle artery, which arises from the internal iliac

Pampiniform plexus of testicular veins- drains venous blood from the testes into the testicular vein

Question 34

Nerves that run I the spermatic cord and what they supply

Answer 34

Genital branch o the genitofemoral nerve- supplies the cremaster muscle

Autonomic nerves

Question 35

Other structures that run through the spermatic cord and their uses

Answer 35

Vas deferens - the duct that transports sperm from the epididymis to the ampulla (a dilated terminal part of the duct), ready for ejaculation

Processus vaginalis- projection of the peritoneum that forms the pathway of descent for the testes during embryonic development. In the adult, it is fused shut

Lymph vessels- These drain into the para-aortic nodes, located in the lumbar region

Question 36

What are the three muscle layers of the vas deferens

Answer 36

Inner layer- longitudinal smooth muscle

Intermediate layer- circular smooth muscle

Outer layer-longitudinal smooth muscle

Question 37

What is testicular torsion

Answer 37

SPermatic cord twists upon itself which can lead to strangulation of the testicular artery (resulting in necrosis of the testis)

Question 38

What is a common cause of testicular torsion

Answer 38

Spasm of the cemasteric muscle fibres which force the testicle to spin around its own cord

A loose testicle in a large peritoneal sac may facilitate this movement