Male Urethra

Question 1

Size

Answer 1

18-20 cm long

Question 2

Extent

Answer 2

Extends from internal urethral orifice in urinary bladder to external urethral meatus at penis end

Question 3

Shape

Answer 3

It shows double curves in flaccid penis

Question 4

Function

Answer 4

Common duct for urinary and genital systems allowing passage of urine and
semen to outside

Question 5

Parts

Answer 5

1. Preprosatatic
2. Prostatic
3. Membranous
4. Penile (spongy)

Question 6

Preprostatic part: size

Answer 6

1-1.5 cm long

Question 7

Preprostatic part: extent

Answer 7

Extending from bladder neck to prostate superior aspect

Question 8

Preprostatic sphincter

Answer 8

Smooth muscle bundles surround bladder neck and preprostatic urethra forming preprostatic sphincter

Question 9

Preprostatic sphincter function

Answer 9

Contracts to prevent ejaculate retrograde flow into bladder so its disruption in bladder neck surgery causes retrograde ejaculation

Question 10

Prostatic part: size and shape

Answer 10

1. 3-4 cm long
2. Widest and most dilatable part

Question 11

Prostatic part: course

Answer 11

Passes downwards and forwards through prostatic substance to emerge from gland anterior aspect above its apex

Question 12

Prostatic part: posterior wall content

Answer 12

1. Urethral crest
2. Seminal colliculus
3. Prostatic sinus

Question 13

Urethral crest

Answer 13

Prominent longitudinal fusiform median ridge

Question 14

Seminal colliculus

Answer 14

Rounded elevation in urethtral crest middle shows 3 openings:
1. Prostatic utricle
2. 2 ejaculatory ducts openings on each side

Question 15

Prostatic utricle

Answer 15

1. Small diverticulum in prostate median lobe (homologues to female uterus)
2. Opens on seminal colliculus summit

Question 16

Prostatic sinus

Answer 16

Groove on each side of urethral crest receiving 15-20 prostatic ducts openings

Question 17

Membranous part: size and shape

Answer 17

1. Shortest (1.5 cm)
2. Least dilatable & narrowest part (with exception of external urethral orifice)

Question 18

Membranous part: course

Answer 18

1. Begins at prostate lower part
2. Passes downwards and forwards in deep perineal pouch being surrounded by sphincter urethrae to
3. Terminate in penis bulb

Question 19

Membranous part: content

Answer 19

1. There are 2 small bulbourethral glands on either side of membranous urethra
2. Glands ducts pierce perineal membrane to open into penile urethra

Question 20

Membranous part: site

Answer 20

1. Called membranous because in deep perineal pouch it lies between 2 membranes
2. Pelvic fascia above and perineal membrane below

Question 21

Penile part: size

Answer 21

15 cm long

Question 22

Penile part: extent

Answer 22

Extending from membranous urethra end to external urethral orifice on glans penis

Question 23

Penile part: course

Answer 23

1. Enters penis bulb upper surface (in superficial perineal pouch)
2. Passes through body and glans penis
3. End by opening to outside through external urethral meatus which is narrowest part of whole urethra

Question 24

Penile part: content

Answer 24

Shows 2 dilatations:
1.Dilatation in bulb (intra-bulbar fossa): receives bulbourethral glands openings
2. Dilatation in glans (navicular fossa): small recess lies on fossa roof (lacuna magna)

Question 25

Urethral sphincters

Answer 25

1. Internal
2. External

Question 26

Internal urethral sphincter

Answer 26

1. Surrounds urethral beginning
2. Involuntary
3. Supplied by autonomic fibers.

Question 27

External urethral sphincter

Answer 27

1. Surrounds membranous urethra
2. Voluntary
3. Supplied by perineal branch of pudendal nerve