anatomy of male urethra

male urethra

1. PRESENTED BY:
S . MADHURI 1 ST YEAR PG

2. REFERENCES:
GRAY’S ANATOMY
KING & NICOL
V.K SHARMA
INDERBIR SINGH HISTOLOGY
INDERBIR SINGH EMBRYOLOGY

3. MALE URETHRA IS A
FIBROMUSCULAR CANAL
EXTENDING FROM BLADDER NECK
TO EXTERNAL URINARY MEATUS
ITS LENGTH IS APPROXIMATELY
20 CM

5. IT IS BROADLY DIVIDED INTO THREE PARTS
PROSTATIC
MEMBRANOUS
SPONGY OR PENILE
PROSTATIC AND MEMBRANOUS TOGETHER FORM
POSTERIOR URETHRA
SPONGY PORTION FORMS ANTERIOR URETHRA

7. pars prostatica
3 CM IS LENGTH
LINED BY TRANSITIONAL
EPITHELIUM
IT IS THE WIDEST AND MOST
DILATABLE PART OF MALE
URETHRA

8. COURSE:BEGINS AT THE NECK OF THE
BLADDER ,RUNS DOWNWARDS AND
SLIGHTLY FORWARDS TO END AT THE
POSTERIOR LAYER OF TRIANGULAR
LIGAMENT(UROGENITAL DIAPHRAGM)

10.  Upon the posterior wall or floor is a
narrow longitudinal ridge, the urethral
crest (verumontanum), formed by an
elevation of the mucous membrane and
its subjacent tissue.it is 15- 17 mm
in length&3mm in height

11. On either side of the crest is a slightly
depressed fossa, the prostatic sinus, the
floor of which is perforated by numerous
apertures, the orifices of the prostatic
ducts from the lateral lobes of the
prostate; the ducts of the middle lobe open
behind the crest.

12. At the forepart of the urethral
crest, below its summit, is a median
elevation, the colliculus seminalis,
upon or within the margins of which
are the orifices of the prostatic
utricle and the slit-like openings of
the ejaculatory ducts.

13.  The prostatic utricle (sinus pocularis )
is also called as the uterus masculinus,
as it is developed from the united lower
ends of the atrophied Müllerian ducts,
and therefore homologous with the
uterus and vagina in the female

15. (pars membranacea)
1.5 – 2 CM IN LENGTH
LINED BY PSEUDO STRATIFIED
COLUMNAR EPITHELIUM
IS THE SHORTEST, LEAST DILATABLE,
AND, WITH THE EXCEPTION OF THE
EXTERNAL ORIFICE, THE NARROWEST
PART OF THE CANAL

16. COURSE:It extends downward and
forward, with a slight anterior
concavity, between the apex of the
prostate and the bulb of the urethra,
perforating the urogenital diaphragm
about 2.5 cm. below and behind the
pubic symphysis.

17.  the membranous urethra is completely
surrounded by the fibers of the
Sphincter urethrae. In front of it the
deep dorsal vein of the penis enters the
pelvis between the transverse ligament
of the pelvis and the arcuate pubic
ligament
The glands of cowper ( bulbo urethral
glands) lie on either side of its posterior
surface

18.  PARS CAVERNOSA; PENILE
URETHRA
 15 CM IN LENGTH
LINED BY PSEUDO STRATIFIED
COLUMNAR EPITHELIUM EXCEPT
FOR TERMINAL 12MM , THE FOSSA
NAVICULARIS , WHICH IS LINED
BY STRATIFIED SQUAMOUS
EPITHELIUM

19. COURSE:extends from the termination of
the membranous portion to the external
urethral orifice. Commencing below the
inferior fascia of the urogenital diaphragm it
passes forward and upward to the front of
the symphysis pubis; and then, in the flaccid
condition of the penis, it bends downward
and forward.

20. it is dilated behind, within the bulb,
and again anteriorly within the glans
penis, where it forms the fossa
navicularis urethræ.
  The external urethral orifice
(orificium urethræ externum; meatus
urinarius) is the most contracted part
of the urethra; it is a vertical slit,
about 6 mm. long.

21.  The lining membrane of the urethra,
especially on the floor of the
cavernous portion, presents the
orifices of numerous mucous glands
and follicles situated in the submucous
tissue, and named the urethral glands
(Littré). Besides these there are a
number of small pit-like recesses, or
lacunæ, of varying sizes.

22. One of these lacunæ, larger than the
rest, is situated on the upper surface
of the fossa navicularis; it is called
the lacuna magna or sinus of guerin
The bulbo-urethral glands open into
the cavernous portion about 2.5 cm.
in front of the inferior fascia of the
urogenital diaphragm.

24. INTERNAL URETHRAL SPCHINTER:
Also known as sphincter vesicae
Involuntary in nature
Supplied by sympathetic nerves from
lower thoracic and upper lumbar
segments
It controls the neck of bladder and
prostatic urethra above openings of
ejaculatory ducts

25. EXTERNAL URETHRAL SPHINCTER:
Also known as SPHINCTER URETHRAE
Voluntary in nature
Supplied by perineal branch of pudendal
nerve(S2 S3 S4)
It controls membranous urethra and is
responsible for the voluntary holding of urine

27. The prostatic urethra is supplied by the
inferior vesical artery.
 The bulbourethral artery supplies the
membranous and bulbar urethra
 penile urethra is supplied by the deep
penile artery, a branch of the internal
pudendal artery.
 In general, venous drainage mirrors the
arterial supply

28. Lymphatics from prostatic and membranous
parts pass mostly to the internal iliac nodes
and partly to the external iliac nodes
Lymphatics from spongy part pass mostly to
deep inguinal nodes but some may end in
superficial inguinal and external iliac

29. Wall of urethra composed of mucous ,
submucous and muscular layers
Mucuous membrane consists of lining
epithelium that rests on connective
tissue
Mucosa shows invaginations into which
mucus glands open

30. The sub mucosa consists of loose connective
tissue.
the muscle coat consists of inner
longitudinal and outer circular layer of
smooth muscle.it is well defined only in
prostatic and membranous urethra,the
penile part is surrounded by ocassional
fibres only

31. The part of urethra extending from
urinary bladder upto the openings of
ejaculatory ducts, is derived from
caudal part of vesico urethral
canal(endoderm).the posterior wall of
this part is derived from the absorbed
mesonephric ducts(mesoderm)

32. The rest of prostatic urethra and the
membranous urethra,are derived from the
pelvic part of definitive urogenital sinus
The penile part of urethra except the
terminal part is derived from the epithelium
of the phallic part of the definitive
urogenital sinus
The terminal part that lies in the glans is
derived from ectoderm

33. RUPTURE OF URETHRA: the urethra
is commonly ruptured beneath the
pubis by a fall astride a sharp
object.this causes extravasation of
urine
HYPOSPADIAS:common anamoly in
which urethra opens on the
undersurface of penis

34. EPISPADIAS: rare condition in which
urethra opens on the dorsum of
penis.this condition is associated with
ectopia vesicae

35. URETHRITIS:inflammation of urethra
Presents with
Discharge
Discomfort during micturition and burning
micturition
Confirmatory test is finding of increased
number of polymorphonuclear leucocytes in
the urethral smear or in sediment of first
vioded urine

36. CAUSES:BROADLY
GONOCOCCAL
NON-GONOCOCCAL

38. STICTURE OF URETHRA : urethral stricture
is a narrowing of the urethra caused by
injury or disease such as
urinary tract infections
can occur as complication of gonococcal and
non gonococcal urethritis

39. soft strictures occur following non
gonococcal urethritis
hard strictures occur following
gonococcal
other causes:
Trauma is more common cause,it can
be physical(eg catheterization ,
urethroscopy)
Chemical (burns from podophyllin ,tca
or diathermy

40. early syphilitic disease
chancroid
herpes genitalis
tuberculosis
bilharzia
lgv