6. MOB TCD
Urogenital Triangle
• Deep pouch
• Superficial pouch
• Perineal membrane
separates the two
• Deep is superior to
perineal membrane
• Roof is pelvic fascia
7. MOB TCD
Deep Pouch in Male
Membranous portion of
the urethra
• Sphincter urethra or
external sphincter of
bladder
• Perineal nerve
• Deep transverse perineal
muscle
•
8. MOB TCD
Deep Pouch in Male
• Bulbourethreal glands
• Internal pudendal artery and
branches
• Artery to bulb
• Dorsal nerve of penis
• Branches of perineal nerve
9. MOB TCD
Deep Pouch in Female
•
•
•
•
•
•
•
•
Vagina
Urethra
Sphincter urethra or external
sphincter of bladder
Perineal nerve
Deep transverse perineal muscle
Internal pudendal artery
Artery to bulb
Dorsal nerve of clitoris
10. MOB TCD
Sphincter Urethrae (Female)
• Sphincter urethrae
in the deep pouch
• Also called external
sphincter of bladder
• Perineal branch of
pudendal S 2,3
11. MOB TCD
Perineal Membrane (Male)
•
•
•
•
•
•
Piercing membrane
Spongy urethrae
Ducts of bulbourethral glands
Artery to bulb
Internal pudendal artery
Deep and dorsal arteries of
penis
• Dorsal nerve of penis
• Deep dorsal vein passes above
membrane
• Enters prostatic venous plexus
15. MOB TCD
Colles’ Fascia
• Attached posteriorly to
perineal membrane
• Sides of pubic arch laterally
• Deep fascia of thigh along a line
drawn from pubic tubercle
• Anterior floor of pouch
• Layer of scrotum
• Surrounds penis as far as glans
• Passes up on to anterior
abdominal wall
16. Membranous Layer of Superficial
or Colles’ Fascia
• Posterior attached to posterior border
of perineal membrane
• Anterior it forms floor of superficial
pouch and forms layer of the scrotum
• Surrounds penis as far as glans
• Then on to anterior abdominal wall
• Attached to fascia lata from a
horizontal line from pubic tubercle
• Rupture of spongy urethra is limited
by the attachment of Colles’ fascia
MOB TCD
17. MOB TCD
Superficial Pouch (Male)
•
•
•
•
Roof
Perineal membrane
Floor
Colles’ or membranous layer of
superficial fascia
• Ruptured urethra in male
• Urine limited by the attachments
of Colles’ fascia in superficial
pouch
18. MOB TCD
Superficial Pouch (Male)
•
•
•
•
•
•
•
•
•
•
Penis corpus spongiosum
Corpora cavernosa
Spongy urethra
Bulbospongiosus muscle
Ischiocavernosus muscle
Superficial transverse perinei muscle
Internal pudendal artery
Deep and dorsal arteries of penis
Dorsal nerves of penis
Scrotal vessels and nerves
19. MOB TCD
Contents Superficial Pouch (Male)
•
•
•
•
•
Root of penis
Corpus spongiosum
Bulb, body and glans
Spongy portion of urethrae
Crura and corpora cavernosa
22. MOB TCD
Penis
• Corpus spongiosum
• Corpora cavernosa
• Consists of erectile
cavernous tissue
• Each enclosed in a fibrous
membrane, tunica albuginea
• Surrounded by Colles’
Fascia
23. MOB TCD
Penis
• Deep artery enters crura of
corpora cavernosa
• Dorsal nerve of penis
• Dorsal artery of penis
• Deep dorsal vein lies on
dorsum between Colles’s
fascia and tunica albuginea
• Passes above perineal
membrane
• Enters prostatic venous
plexus
24. MOB TCD
Penis
• Erectile tissue
• Helicine arteries
• Fibrous saccules arterioles
enter directly
• Dorsal vein open
• Parasympathetic causes
erection L2,3,4
• Ejaculation is via the
sympathetic impulses from
L1-L2
25. MOB TCD
Corpus Spongiosum
•
•
•
•
•
•
•
•
•
Bulb posterior dilatation
Body (horizontal)
Glans dilated anteriorly
Spongy urethra
Dilated posteriorly in the bulb
Uniform in body
Dilated in the glans
Fossa navicularis
Meatus vertical slit
27. MOB TCD
Spongy Urethra
•
•
•
•
•
Urethra unprotected
Before it enters bulb
Ducts of bulbo-urethral glands
Enter intrabulbar fossa
Littre’ glands end in navicular
fossa
28. MOB TCD
Muscles in Superficial Pouch (Male)
• Bulbospongiosus muscle
• Ischiocavernosus muscle
• Superficial transverse perinei
muscle
• Supplied by perineal
branches of pudendal nerve
• Enter pouch by piercing
Colles’ fascia
29. MOB TCD
Vessels and Nerves
• Deep and dorsal arteries of
penis
• Deep dorsal vein
• Scrotal nerves
• Perineal nerve
• Dorsal nerve of penis
30. MOB TCD
Lymphatics
• Skin of scrotum to medial
superficial inguinal glands
• Testes to para aortic glands
at L2
31. MOB TCD
Nerve Supply
• Preganglionic of sympathetic
from L1 and L2 cause
ejaculation
• Parasympathetic
preganglionic from S2,3,4
cause erection
38. MOB TCD
Superficial Pouch (Female)
• Cutaneous anteriorly
• Ilioinguinal nerve
• Labial vessels and nerve
posteriorly
• Motor
• Perineal branches of pudendal
39. MOB TCD
Structure of Female Urethra
•
•
•
•
•
•
Muscular layer continuous with bladder
Spongy erectile tissue
Plexus of veins
Mucous membrane transitional
Distal non-keratinising stratified squamous
No fascia between lower two thirds of urethra
and vagina
40. MOB TCD
Vagina
• Fornices, gutters which
surround the cervix
• Anterior shallow
• Posterior deeper
• Superior covered with
peritoneum of the pouch of
Douglas
• Lateral: uterine artery above
ureter
41. MOB TCD
Vagina
• Upper portion of the vagina is
clasped
• By the pubovaginalis portion of
the levator ani
• Bulbospongiosus muscles
surrounds outlet
• Hymen
42. MOB TCD
Vagina
•
•
•
•
Erectile tissue
Muscular wall
Pelvic fascia
Non-keratinised stratified squamous
epithelium
• Urethra lower third anterior wall
• No fascia between lower two thirds
of urethra and vagina
44. MOB TCD
Anal Canal
• Anorectal junction: below
ampulla of rectum
• Anus: 4 cm
• Anterior: perineal body
• Posterior: anococcygeal body
• Lateral: ischiorectal fossae
45. MOB TCD
Anal Canal
• Upper two thirds
• Columnar epithelium
• Anal columns contain radicles
of superior rectal artery and
veins
• 4, 7, 11 o’clock position
• Anal valves along
pectinate line
• Anal sinus, Hilton white line;
internal sphincter
• Subcutaneous deep
• Lower third skin
47. MOB TCD
Muscles of Anal Canal
•
•
•
•
•
Anorectal ring
Puborectalis
Internal sphincter
Upper two thirds
Perianal fascia is medial to
deep and superficial sphincter
• Passes to lateral wall forms
pudendal canal
• Above subcutaneous sphincter
48. MOB TCD
Blood and Nerve Supply
•
•
•
•
•
•
Mucosa upper two thirds
Superior rectal artery
Autonomic nerves
Lower third
Inferior rectal
Somatic nerves
49. MOB TCD
Venous Drainage
•
•
•
•
•
•
•
Mucosa upper two thirds
Superior rectal vein
Portal system
Lower third
Inferior rectal vein
Vein into systemic system
Portal systemic anastomosis
4,7,11 o’clock
50. MOB TCD
Lymphatic Drainage
• Upper third
• Pre-aortic inferior mesenteric
• Waldeyer’s fascia passes from
sacrum to the ampulla of rectum
• Encloses superior rectal vessels
and lymphatics
• Internal iliac
• Lower third
• Inferior rectal cross ischiorectal fossa
• Medial superficial inguinal glands
51. MOB TCD
Embryology of Anal Canal
•
•
•
•
Upper two thirds
Cloaca
Lower third
Proctodeum
52. MOB TCD
Ischiorectal Fossa
• Wedge shaped fossa
• Apex: origin of levator ani
from obturator internus
• Lunate fascia
• Base: perianal fascia and
subcutaneous fat
• Medial: levator ani
• External anal sphincters
MOB TCD