male urethra
Last reviewed 01/2018
Anatomical divisions:
- posterior urethra
- prostatic urethra:
- 3-4 cm in length
- verumontanum is a prominence on the posterior wall; ejaculatory ducts open on either side
- membranous urethra:
- 2 cm in length
- from apex of the prostate to the bulb of the penis
- site of sphincteric activity
- anterior urethra:
- includes bulbar and penile urethra
- surrounded by corpus spongiosum
- involved in emptying of urine at end of voiding and emission of semen during ejaculation
- corpora cavernosa lie dorsally
Blood supply:
- branches from internal pudendal artery; run through the corpus cavernosum in the 5 'o' clock and 7 'o' clock positions
- branches of dorsal arteries to the penis; run proximally from glans penis into corpus cavernosum
Determinants of sphincteric activity:
- inner layer of smooth muscle
- outer layer of striated muscle, innervated by S2 and S3
Histology:
- transitional cell epithelium proximally
- squamous cell epithelium near external meatus at fossa navicularis