This document discusses the anatomy of the urogenital triangle and classification of urethral injuries. It begins with an overview of the bony pelvis and ligaments, followed by the muscles that support the pelvic floor including the levator ani and coccygeus. It then describes the urogenital diaphragm and its contents. Several classifications of urethral injuries are presented, including the McCallum & Col Pinto classification for posterior injuries and the AAST classification system for severity grading. Injuries can be anterior or posterior, with posterior injuries often associated with pelvic fractures from trauma.

1. ANATOMY OF UROGENITAL
TRIANGLE AND
CLASSIFICATION OF URETHRAL
INJURIES
Dept of Urology
Govt Royapettah Hospital and Kilpauk Medical College
Chennai
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2. Moderators:
Professors:
• Prof. Dr. G. Sivasankar, M.S., M.Ch.,
• Prof. Dr. A. Senthilvel, M.S., M.Ch.,
Asst Professors:
• Dr. J. Sivabalan, M.S., M.Ch.,
• Dr. R. Bhargavi, M.S., M.Ch.,
• Dr. S. Raju, M.S., M.Ch.,
• Dr. K. Muthurathinam, M.S., M.Ch.,
• Dr. D. Tamilselvan, M.S., M.Ch.,
• Dr. K. Senthilkumar, M.S., M.Ch.
Dept Of Urology, KMC and GRH,
Chennai
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3. BONY PELVIS
• Bony pelvis consists of two innominate bones-fused posteriorly to sacrum and
to each other anteriorly.
• Each innominate bone is composed of ilium,ischium and pubis.
• At the pelvic inlet,the true and false pelvis are seperated by the arcuate line.
• Arcuate line extends from the sacral promontory to the pectineal line of pubis.
• The inferior pelvic outlet is closed by the pelvic floor.
Dept Of Urology, KMC and GRH,
Chennai
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4. LIGAMENTS
• Sacrospinous ligament:
Extends from the ischial spine to the lateral margins of the sacrum
and coccyx.The greater and lesser sciatic foramen are above and
below the ligament.
• Sacrotuberous ligament:
Extends from the ischial tuberosity to the coccyx.
Dept Of Urology, KMC and GRH,
Chennai
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5. MUSCULAR SUPPORTS OF THE PELVIC
FLOOR
• Muscles that form the pelvic diaphragm include the
Levator ani and the coccygeus.
• Levator ani is composed of two major muscles from
medial to lateral-Pubococcygeus and Iliococcygeus.
Dept Of Urology, KMC and GRH,
Chennai
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6. PUBOCOCCYGEUS
• Bulkier medial part that arises from the back of body of pubis
and anterior portion of arcus tendineus.
• The inner border forms the margin of the urogenital hiatus
,through which pass the urethra ,vagina and anorectum.
• Portions of the Pubococcygeus include Pubovaginalis,
Puboanalis and Puborectalis.
Dept Of Urology, KMC and GRH,
Chennai
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7. • Iliococcygeus:
Thin lateral part of the levator ani that
arises from the arcusa tendineus of the levator ani to the
ischial spine.
• Coccygeus:
Extends from the ischial spine to coccyx
and lower sacrum and forms the posterior part of the
pelvic diaphragm.It sits on the pelvic surface of the
sacrospinous ligament.
Dept Of Urology, KMC and GRH,
Chennai
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8. ARCUS TENDINEUS
• Arcus tendineus of the Levator ani is a dense
connective tissue structure
• Extends from the pubic ramus to the ischial
spine and courses along the surface of the
obturator internus.
Dept Of Urology, KMC and GRH,
Chennai
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9. UROGENITAL DIAPHRAGM(TRIANGLE)
• The weakest point in the pelvic floor ,Urogenital hiatus,is
bridged by the Urogenital diaphragm – a structure
unique to humans.
• It is triangular and bridges the gap between the inferior
pubic rami bilaterally and the perineal body.
• Posteriorly,it ends abruptly
Dept Of Urology, KMC and GRH,
Chennai
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10. • Perineal body represents the point of fusion
between the free posterior edge of the urogenital
diaphragm.
• Urogenital diaphragm seperates the deep
perineal sac from the upper pelvis.
• Urogenital diaphragm is made of 2 paired
muscles –the Deep transverse perineal muscle
and Superficial transverse perineal muscle.
Dept Of Urology, KMC and GRH,
Chennai
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11. • Fascia of the urogenital diaphragm include the
Superficial and Deep perineal fascia,lining the inferior
surface and superior surface of the urogenital diaphragm
respectively
• Urogenital diaphragm provides structural support for the
distal urethra.
Dept Of Urology, KMC and GRH,
Chennai
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12. ARTERIES:
• Bulbar artery of penis
• Dorsal artery of penis
• Perineal artery
• Int.pudendal
• Ext pudendal
VEINS
• Dorsal veins of penis
• Int. pudendal vein
• Ext. pudendal vein
Dept Of Urology, KMC and GRH,
Chennai
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13. DEEP PERINEAL POUCH
Superior border:
Lacks a definite superior border,extends into the pelvis.
Inferior border:
Perineal membrane(Superficial perineal fascia).
Dept Of Urology, KMC and GRH,
Chennai
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14. CONTENTS:
1.Muscles:
Deep transverse perineal muscle.
External sphincter of urethra.
2.Membranous portion of Urethra.
3.Bulbourethral (Cowper’s gland)
Dept Of Urology, KMC and GRH,
Chennai
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15. SUPERFICIAL PERINEAL POUCH
Superior border:
Perineal membrane(superficial perineal fascia)
Inferior border:
Colles fascia.
Dept Of Urology, KMC and GRH,
Chennai
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16. CONTENTS
1.Muscles:
Ischiocavernosus muscle
Bulbospongiosus
Superficial transverse perineal muscle.
2.Crura of penis/Crura of clitoris
3.Bulb of penis/Vestibular bulbs.
4.Greater vestibular glands(female)
Dept Of Urology, KMC and GRH,
Chennai
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17. PERINEAL BODY
• Perineal body (Central tendon of perineum) is a
pyramidal fibromuscular mass in the midline of
perineum at the junction between the urogenital
triangle and anal triangle.
• Found in both males and females.
Dept Of Urology, KMC and GRH,
Chennai
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18. Muscles converging in Perineal body:
1.Superficial transverse perineal muscle.
2.Bulbospongiosus
3.Deep transverse perineal muscle.
4.Anterior fibers of Levator ani.
5.External urethral sphincter
6.External anal sphincter.
Perineal body is essential for the integrity of the
pelvic floor.
Dept Of Urology, KMC and GRH,
Chennai
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19. MALE URETHRA
• Male urethra extends from the internal urethral orifice in
the bladder to the external urethral orifice at the tip of
penis.
• Roughly ‘S’ shaped.
• Length varies from 17.5 to 20 cm.
• Based on consensus opinion in WHO conference
2002,urethra can be divided into six separate areas.
Dept Of Urology, KMC and GRH,
Chennai
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20. 1.Fossa navicularis:
Contained within the spongy erectile tissue of glans penis.Lined
with stratified squamous epithelium.
2.Penile or pendulous urethra:
Lies distal to investment of ischiocavernosus muscle,invested by
corpus spongiosum.Lined with simple squamous epithelium.
3.Bulbous urethra:
Covered by midline fusion of ischiocavernosus and invested by
bulbospongiosus.Distally squamous epithelium and proximally
transitional.
Dept Of Urology, KMC and GRH,
Chennai
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21. 4.Membranous urethra:
Shortest,least dilatable and with the excp.of
ext.urethral orifice ,the narrowest part of the
canal.Measures 2 cm in length.Extends downward and
forward ,perforating the urogenital diaphragm .
Only portion of the male urethra that is not invested by
another structure.Lined by transitional epithelium.
5.Prostatic urethra:
Widest,most dilatable part.Measures 3cm in
length.Runs vertically through the prostate and at its
midpoint turns 35 deg anteriorly,angulation varies 0 to 90
6.Bladder neck.
Dept Of Urology, KMC and GRH,
Chennai
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22. • Urethral crest :
Narrow ridge on the posterior wall of prostatic
urethra
• Verumontanum:
Median elevation at forepart of urethral crest.
• Prostatic utricle:
Mullerian duct derivative opening at apex of
verumontanum.
Dept Of Urology, KMC and GRH,
Chennai
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23. • The internal sphincter muscle
of urethra: located at the
bladder's inferior end and the
urethra's proximal end at the
junction of the urethra with the
urinary bladder.
• The external sphincter muscle
of urethra (sphincter urethrae):
located at the bladder's distal
inferior end in females and
inferior to the prostate (at the
level of the membranous
urethra)in males is a
secondary sphincter to control
the flow of urine through the
urethra.
Dept Of Urology, KMC and GRH,
Chennai
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24. BLOOD SUPPLY OF URETHRA
• The arterial supply of the male urethra is primarily by the
Bulbar arteries which are proximal br. of Internal
pudendal artery.
• Distally, it is supplied by the Dorsal artery of the
penis,which is a terminal br.of int. pudendal artery and
collaterals from corporal bodies.
• This dual blood supply allows the urethra to be detached
at either end without compromise to its viability,a fact
frequently used in Urethroplasty.
Dept Of Urology, KMC and GRH,
Chennai
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25. PERINEUM
• The perineum is a diamond shaped outlet bounded
anteriorly by the pubic arch and the arcuate ligaments of
the pubis.
• Posteriorly by the tip of coccyx.
• Laterally,by the inferior rami of pubis and ischium.
• Transverse line between the ischial tuberosities divides
the perineum into an anterior urogenital triangle and a
posterior anal triangle.
Dept Of Urology, KMC and GRH,
Chennai
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26. COLLES’ FASCIA
• In the anterior triangle,Colles’ fascia attaches at its
posterior margin to the perineal body.
• The fascia curves below the superficial transverse
perineal muscle and projects forward as two layers
attached laterally to the ischium and inferior pubic
ramus.
• The loose superficial layer is continuous with the more
substantial dartos fascia of the scrotum.
• The deep membranous layer of Colles fascia forms a
roof over scrotal cavity,seperating it from superficial
perineal pouch. Dept Of Urology, KMC and GRH,
Chennai
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27. • Anteriorly ,Colles fascia fuses and becomes continuous
with the membranous layer of the subcutaneous tissue
of the anterior abdominal wall.(Scarpa’s fascia).
• Laterally,Colles fascia fuses to the pubic arch and with
the fascia lata.
• Posteriorly ,fuses with the posterior aspect of the
perineal membrane.
Dept Of Urology, KMC and GRH,
Chennai
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28. Injury to the urethra can be broadly classified as Anterior
and Posterior urethral injury.
Posterior urethral injuries
Injuries to the posterior urethra occur with pelvic
fractures, which are commonly caused by road traffic
accidents, crush injuries or falls from height. About two-
thirds (70%) of pelvic fractures occur as a result of motor
vehicle accidents
Dept Of Urology, KMC and GRH,
Chennai
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29. Aetiology of anterior urethral injuries
Blunt trauma
• Vehicular accidents
• Fall astride
• Kicks in the perineum
Blows in the perineum from bicycle handlebars, tops of fences, etc.
Sexual intercourse
• Penile fractures
• Urethral intraluminal stimulation
Penetrating trauma
• Gunshot wounds
• Stab wounds
• Dog bites
• External impalement
• Penile amputations
Iatrogenic injuries
• Endoscopic instrumentations
• Urethral catheters-dilators
Dept Of Urology, KMC and GRH,
Chennai
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30. McCALLUM & COL PINTO
CLASSIFICATION
Based on radiographic appearances of posterior injuries.
Type 1: Urethral contusion or stretch injury,passage of
contrast into bladder, no extravasation.
Type 2: Partial or complete rupture above urogenital
diaphragm,contrast may reach bladder, supra
diaphragmatic extravasation.
Type 3: Complete disruption of membranous
urethra,contrast does not reach bladder.Extravasation
both supra and infra diaphragmatic.
Dept Of Urology, KMC and GRH,
Chennai
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31. GOLDMAN ET AL CLASSIFICATION
• Type 1:
Posterior urethra intact
but stretched by pelvic
hematoma.
• Type 2:
Partial or complete
prostatomembranous urethral
rupture above intact urogenital
diaphragm.
Dept Of Urology, KMC and GRH,
Chennai
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32. • Type 3:
Partial or complete combined
anterior/posterior urethral rupture with
rupture of urogenital diaphragm.
Dept Of Urology, KMC and GRH,
Chennai
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33. • Type 4:
Bladder neck injury with extension into posterior
urethra
• Type 4a:
Base of bladder injury with periurethral
extravasation.
.
Dept Of Urology, KMC and GRH,
Chennai
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34. • Type 5:
Partial or complete anterior urethral injury
Dept Of Urology, KMC and GRH,
Chennai
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35. AAST classification
• Grade 1:
contusion :blood at meatus;urethrography normal.
• Grade 2:
stretch injury :elongation of urethra without
extravasation on urethrography.
• Grade 3:
partial disruption :extravasation of contrast at injury
site with contrast visualisation in bladder.
Dept Of Urology, KMC and GRH,
Chennai
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36. • Grade 4:
complete disruption :extravasation on
urethrography,contrast at injury site without visualisation
in bladder;less than 2 cm urethral seperation.
• Grade 5:
complete disruption; complete transection with
more than 2 cm seperation or extension into prostate or
vagina.
Dept Of Urology, KMC and GRH,
Chennai
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37. CLASSIFICATION OF POSTERIOR
URETHRAL INJURIES –AL RAFAEI ET AL.
Ia: Proximal avulsion of the prostate from the bladder neck
Ib: Incomplete or complete transverse transprostatic urethral rupture.
II : Stretching of the membranous urethra.
III : Incomplete or complete pure rupture of prostato-membranous
junction.
IV :Incomplete or complete pure rupture of bulbo-membranous(infra
diaphragmatic)
V : Incomplete or complete , variable , combined urethral injuries.
Dept Of Urology, KMC and GRH,
Chennai
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38. Dept Of Urology, KMC and GRH,
Chennai
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