ANATOMY'OF'PROSTATE''

'DEVELOPMENT:''Endodermal*outgrowth*of*the*prostatic*urethra.*

Stroma*and*smooth*muscle*from*the*smooth*muscle*around.*

*

• Accessory*male*reproductive*organ.*

• Contributes*to*30%*seminal*fluid.*

'SITE:'• Lower*part*of*lesser*pelvis*behind*inferior*border*of*symphysis*pubis,*in*front*of*

rectum*and*below*neck*of*bladder.'• ''DIMENSIONS:'• AP:*2cm*

• Vertical:*3cm*

• Transverse:*4cm*

• 2cmx3cmx4cm*

'CAPSULES:'• INNER'True'capsule:*fibroImuscular*

structure.'• OUTER'False'capsule*(prostatic*sheath):*

condensed*visceral*pelvic*fascia.*

• Between*these*two*capsules*lies*the*prostatic*venous*plexus.*

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PROSTATE gland: �  It$ is$ an$ accessory gland of$ male reproductive

system,$which$surrounds$the$prostatic urethra.$

�  It$lies$in$the$lower part of$the$lesser pelvis behind$the$inferior$border$of$the$symphysis pubis, in$front$of$the$rectum$&$below$neck$of$the$bladder.$

1.  Site:!

�  It$ contributes$ to$3 0 %$ o f $ t h e$seminal fluid.!

SP$R$

SHAPE,'DESCRIPTIONS,'&'RELATIONS:'

• Apex:*inferiorly.*–*rests*on*superior*

fascia*of*urogenital*diaphragm*(roof*of*deep*perineal*pouch)'• Base:*superiorly*(below*neck*of*bladder)*–*contains*part*of*prostatic*venous*

plexus.'• Anterior*surface*–*lies*behind*lower*part*of*the*symphysis*pubis,*retroI*pubic*

space*of*Retzius*and*prostaticvenous*plexus;*connected*to*pubic*bodies*by*puboI

prostatic*ligaments.'• 2*Rt.*And*Lt.*inferoIlateral*surfaces*–*convex*and*related*to*levator*ani*(levator*

prostate).'• Posterior*surface*I**flat*and*related*to*ampulla*of*rectum*and*separted*from*it*by*

rectoIvesical*pouch*(fascia*of*Denonvilliers).*Near*its*upper*border,*pierced*by*2*

ejaculatory*ducts.'*

! FASCIA'OF'DENONVILLIERS:'

• Prostatic*sheath*(red)*touches*fascia*of*Denonvilliers*(orange).'• The*autonomic*innervation*of*the*corpora*of*penis*runs*close*to*posteroIlateral*

aspect*of*the*prostatic*capsule*"*at*risk*for*damage*in*radical*prostatectomy*

surgery*(removal*of*prostate*with*both*capsules*of*prostate*along*with*the*lymph*

nodes).''''''

�  It$ is$convex and$ lies$behind$ the$ lower part of$ the$symphysis pubis,$ retro% &pubic% space% of% Retzius$ &$prostatic$venous$plexus.$$

�  Its$ upper$ part$ is$ connected$ to$ the$pubic bodies by$pubo -prostatic ligaments.$

c.   Anterior$surface:$$

�  It$ is$convex and$ lies$behind$ the$ lower part of$ the$symphysis pubis,$ retro% &pubic% space% of% Retzius$ &$prostatic$venous$plexus.$$

�  Its$ upper$ part$ is$ connected$ to$ the$pubic bodies by$pubo -prostatic ligaments.$

c.   Anterior$surface:$$

�  The$ prostate$ is$ easily$ palpated$ by$ a$ finger$ in$ the$rectum.$$

"  The$recto -vesical fascia is$attached$above$to$the$floor$of$recto -vesical pouch and$below$to$the$perineal body.$

Fascia&of&Denonvilliers!

–  The$prostatic sheath is$touching$with$the$fascia$of$Denonvilliers.$

–  The$autonomic innervation to$the$corpora$of$the$penis$ are$ running$ close$ to$ the$ posterolateral$aspect$of$the$prostatic capsule.$

• The*neural*bundle*(star*in*

diagram)*located*posterior*to*

prostate.'• Located*anterior*to*prostatic*

capsule,*fascia*of*Denonvilliers*

posteriorly,*levator*fascia*

Inferiorly.!'• "!common!cause!of!erectile!

dysfunction/!impotence!during!transurethral*prostatectomy*(done*in*BPH).'

''RELATIONS'OF'PROSTATE:'• Anterior:*symphysis*pubis*

• Posterior:*rectum*

• Inferior:*its*apex*is*rested*on*deep*perineal*pouch*(superficial*fascia*of*urogenital*diaphragm)*

• Superior:*its*base*is*related*to*neck*of*bladder.*• Laterally:*levator*ani.**

LOBES'OF'PROSTATE:''5'LOBES'(anatomically)'

*

• Anterior*lobe*–*front*of*prostatic*urethra*(pic*3).*• Lateral*LOBES*I**lateral*to*urethra*(pic*2).*• Posterior*–*behind*prostatic*urethra,*BELOW*ejaculatory*ducts*(pic*3)*"*

CANCER.*

• Middle*–*between*upper*part*of*prostatic*urethra*and*ejaculatory*ducts*"*BPH.*! When*enlarged,*produces*UVULAE'VESICAE'(elevated'mucosa'of'

lower'trigone)'" 'obstruction'to'flow'of'urine.''''''''

–  They$ $ are$ at$ risk$ of$ damage$ during$ radical prostatectomy (operation$ done$ in$ localized% cancer%prostate,$ it$ involves$ removal$ of$ prostate% with$ $ both$prostatic$capsules%&$lymph$nodes).$

–  The$neural$bundle$is$located$posterior$to$the$prostate.$–  They$are$between$ the$prostatic capsule (pelvic$ fascia)$

anteriorly,$ fascia$ of$ Denonvilliers$ posteriorly$ &$levator fascia inferiorly.$

b. Lobes: 5 1. Anterior: in front of prostatic urethra (fibro-muscular) 2. Rt. And Lt. lateral lobes: lateral to urethra. 3. Posterior lobe: lies behind the prostatic urethra, but

below the ejaculatory ducts. (cancer) 4. Middle lobe: between the upper part of prostatic

urethra and the ejaculatory ducts. (Benign prostatic hyperplasia (BPH) When enlarged it produce uvula vesicae (elevated

mucosa of the lower trigone obstruction to flow of urine.

'ZONES'OF'PROSTATE:*used*in*pathology*

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''''''

• PERIPHERAL'ZONE:'*bulk*of*apical,*posterior,*lateral*aspects*of*prostate.**! 70%*glandular*tissue*of*prostate.*

! 75%'carcinomas*(does*not*undergo*benign*hyperplasia)*• CENTRAL'ZONE:'*

! 25%*glandular*tissue.*

! Surrounds*ejaculatory*ducts.*

! 10%'of'carcinomas.'• TRANSTIONAL'ZONE:'='MIDDLE'LOBE.'

! Surrounds*urethra*and*above*ejaculatory*ducts.'! 5%'carcinomas.'! Main'site'for'BPH.'

• ANTERIOR'ZONE:'='Anterior'lobe'! Fibromuscular,*nonIglandular*tissue.'! Extends*from*neck*of*bladder*to*external*urethral*sphincter.'

'BLOOD'SUPPLY:'• Inferior*vesical*–*anterior*division*of*internal*iliac*artery.'• Middle*rectal'• Internal*pudenal'*'VENOUS'SUPPLY:'• Prostatic*venous*plexus*–*SANTORINI'PLEXUS.'• Present*only*in*front*and*sides*of*the*prostate.'• Drains*into*internal*iliac*veins"which*communicates*with*internal*vertebral*

venous*plexus*through*lateral*sacral*veins*(valveless).'

�  Peripheral$ zone$ constitutes$ the$ bulk$ of$ apical,$posterior and$lateral aspects$of$the$prostate.$

�  It$contains$70%$$glandular$prostate$gland.$$�  75%$of$all$prostate$carcinoma.$

–  This$ zone$does not undergo$ benign hyperplasia.!

6.  Zones of prostate:!

Superior$view$

�  Peripheral$ zone$ constitutes$ the$ bulk$ of$ apical,$posterior and$lateral aspects$of$the$prostate.$

�  It$contains$70%$$glandular$prostate$gland.$$�  75%$of$all$prostate$carcinoma.$

–  This$ zone$does not undergo$ benign hyperplasia.!

6.  Zones of prostate:!

Superior$view$

• Responsible'for'spread'of'cancer'to'lumbar'vertebrae'and'cranium.'NERVE'SUPPLY:'• Inferior*hypogastric*(pelvic)*plexus.*

• Lateral*to*rectum.*

• PARASYMPATHETIC:*pelvic*splanchnic*nerves*–*S2,3,4*"*SECRETION*(active*

gland).*

• SYMPATHETIC:*T11,12;*L1,2;*I*sacral*sympathetic*chain*+*hypogastric*nerves*"*

EXPULSION*OF*PROSTATIC*FLUID.*

• Ejaculation'is*controlled*by*the*SYMPATHETIC*NS*#*contraction*of*SM*stroma*

of*the*bladder*neck*(sphincter'vesicae)*#*expulsion*of*prostate*content*and*

closure*of*bladder*neck,*preventing*retrograde'ejaculation'(semen*enters*

bladder;*can*also*be*caused*by*injury*to*nerves*in*retroperitoneal*

lymphadenectomy*in*PCa).'

LYMPATIC'DRAINAGE:'

• Internal*iliac*#*ParaIaortic*nodes.'• Also*to*sacral*and*external*iliac*#*paraIaortic*LN.'

# 'HISTOLOGY:'

• Numerous*branched*glands*supported*with*a*dense*SM*and*CT*stroma.'• PSEUDOZCOLUMNAR'EPITHELIUM'of*varying*height:'

! Contain*apical*secretory*granules.'! BASAL*CELLS*found*between*columnar*cells*for*regeneration*of*epithelium.'! Prostatic*concretion*formed*by*condensed*prostatic*secretions.'! Their*numbers*increase*with*age.'

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