Male Urethra Development

Question 1

Preprostatic and upper part of prostatic urethra

Answer 1

Derived from: vesicourethral canal and mesonephric ducts absorbed parts

Question 2

Lower part of prostatic urethra and membranous urethra

Answer 2

Derived from: pelvic part of
definitive uro-genital sinus

Question 3

Spongy (penile) urethra

Answer 3

1. Endodermal cells lining phallic part lumen of definitive urogenital sinus proliferate to form urethral plate
2. Phallus pulls urethral folds forming urethral groove lateral walls
3. This groove does not
   reach most distal part of elongated phallus
4. Urethral canal is formed by meeting and fusion of urethral folds
5. It ends blindly anterior at glans penis

Question 4

Terminal (glandular) part

Answer 4

1. Developed by growth of ectodermal cells cord from glans tip
2. It becomes canalized and communicates with urethral canal

Question 5

Congenital anomalies

Answer 5

1. Hypospadius
2. Epispadius

Question 6

Hypospadius

Answer 6

Urethra opens on penis under surface due to failure of fusion of urethral groove edges

Question 7

Epispadius

Answer 7

Urethra opens on penis dorsum may occur as isolated defect or most often associated with bladder exstrophy