Lecture 24: Perineum

Question 1

What are the boundaries of the perineum? 
Anterior
Posterior 
Lateral
Superior
Inferior

Be able to label the parts of the perineum in male and female on the blocked images

Answer 1

Anterior: pubic symphysis
Posterior: coccyx
Lateral: ischiopubic ramus (anteriorly) and sacrotuberous ligaments (posteriorly)
Superior: pelvic diaphragm
Inferior: skin of external genitalia and anal canal

Question 2

The perineum consists of which triangles?

Answer 2

Urogenital (urethra and genitalia) and Anal triangles (anal canal and anus)

Question 3

What are the contents of the anal triangle?

Answer 3

Anal canal
External anal sphincter
Internal anal sphincter

Question 4

What is the ischiorectal fossae and its borders?

Contents?

Answer 4

space between obturator internus + ischium (lateral border) and levator ani + anal canal (medial border), base is skin.
-Fat, nerves and vessels .

Question 5

What is the pudendal canal?

Answer 5

Space between the ischiorectal fossae and obturator internus that contains the pudendal n, internal pudendal a. and internal pudendal v.,

Question 6

What is the blood supply of the anal triangle?

What is the innervation of the anal triangle and what does it innervate?

Answer 6

Internal Pudendal A./V -> Inferior Rectal A/V

Pudendal N. -> Inferior rectal N. - anal sphincter and skin

Question 7

What are the parts of the urogenital triangle?

Answer 7

superficial perineal space

deep perineal space (deep to perineal membrane)

Question 8

What are the major components of the deep perineal space in males?

Be able to identify the structures on the blocked image

Answer 8

• superior and inferior fascia
• Deep transverse perineus muscle
• external urethral sphincter
• membranous urethra that relaxes during urination and ejaculation
• bulborethral/cowpers glands that make mucus during ejaculation

Question 9

What are the major components of the deep perineal space in females?

Be able to identify the structures on the blocked image

Answer 9

• superior and inferior fascia
• deep transverse perineus muscle
• external urethral sphincter
• compressor urethrae
• vagina

Question 10

What are the major components of the superficial perineal space in males?

Be able to label these on the blocked image

Answer 10

Two crura
Bulb of penis (covers the muscles)
Ischiocavernosus m. 
Bulbospongiosus m. 
superficial transverse perineus muscle

Question 11

What are the parts and contents of the shaft of the
penis?

Be able to label these on the blocked image

Answer 11

Corpora cavernosa, urethra, corpus spongiosum, external urethral orifice
Vessel: dorsal artery, vein and nerve, deep artery

Question 12

What is the female external genitalia (vulva) and what does it contain?

Be able to label parts on the blocked image

Answer 12

2 Labia majora
2 Labia minor
1 clitoris

Question 13

What is the vestibule of the vagina and what are its parts?

Be able to label parts on the blocked image

Answer 13

surrounded by the labia minora

External urethral orifice
Vaginal orifice
Paraurethral glands/orifices
Greater vestibular glands/orifices

Question 14

What is the clitoris and its parts?

Be able to label parts on the blocked image

Answer 14

Crura (covered by ischiocavernosus m.)
corpora cavernosus merging into a body
glans (externally visible)

Question 15

What are the major components of the superficial perineal space in females?

Be able to label these on blocked image

Answer 15

Bulbs of the vestibule
Bulbospongiousus m. 
Greater vestibular glands
Superficial transverse perineus m. 
Clitoris
Ischiocavernosus m.

Question 16

What is the blood supply to the urogenital triangle and what do they supply specifically?

Answer 16

Femoral A. > External Pudendal A. > Scrotum/Labia majora + clitoris

Internal Iliac A. > Internal Pudendal A. > most perineal structures

Question 17

What innervates the urogenital triangle and what do they supply specifically?

Answer 17

S2-S4 > Pudendal N. > Perineal N. (scrotum, urethras, labias, motor to ischio, bulbo, deep and superficial transverse, + Dorsal N. (penis/clitoris, motor to urethral sphincter )

Question 18

What fibers does the pudendal n. carry?

Answer 18

• Preganglionic parasympathetic and postganglionic sympathetic to glands
• somatic and sensory fibers to muscles and skin of perineum

Question 19

What are the causes of male impotence?

Answer 19

• prostatic nerve plexus damage (no erection)
• atherosclerosis (no blood supply)
• Type 2 DM
• -spinal cord injury
• hormonal or psych disorders

Question 20

What structures drain to the superficial inguinal nodes?

What structures drain to the internal iliac nodes?

Answer 20

• superficial perineal space, distal vagina, and anal canal below pectinate line
• deep perineal space, proximal vagina

Question 21

What is an episiostomy?

Answer 21

• incision done through the posterior vag wall, bulbo, superficial transverse, skin and fascia to open up cavity for childbirth (could be midline or medio-lateral)
• repaired with 3 layers of incision