Transcript Pudendal - UQMBBS-2013

Question
• Blood supply of the rectum?
• Superior rectal artery (inferior mesenteric)
• Middle rectal artery (anterior division of internal iliac)
• Inferior rectal artery (internal pudendal)
Nerves of the Pelvis
• Pudendal
• S2-S4
• Sensory to genitalia; muscular branches to perineal muscles,
external urethral sphincter, external anal sphincter
• Pelvic splanchnic
• S2-S4
• Pelvic viscera via inferior hypogastric and pelvic plexuses
• Nerve to levator ani and coccygeus
• S3-S4
• Levator ani and coccygeus muscles
Revision on Inguinal Canal
Spermatic Cord
• Contains structures to and from testes
• Begins at deep inguinal ring, lateral to inferior epigastrics
• Fascial coverings:
• Internal spermatic fascia (transversalis fascia)
• Cremasteric fascia (internal oblique) – contains cremaster muscle
• External spermatic fascia (external oblique)
• Contents:
• Ductus (vas) deferens
• Testicular artery, cremasteric artery, deferential artery,
pampiniform plexus
• Sympathetics, genital branch of genitofemoral nerve
• Vestige of processus vaginalis
• Lymphatics
Anatomy of the Scrotum
• Cutaneous sac
• Dartos fascia (continuous with
Scarpa and Colles fascia)
• Dartos muscle
• Septum, scrotal raphe
• Innervation: Genital branch of
genitofemoral nerve (anterolateral
surface)
• Posterior scrotal nerves (internal
pudendal, S2-S4)
Anatomy of Testes
• Tunica vaginalis = closed peritoneal sac =
closed-off remnant of processus vaginalis
in embryo
• Testis covered by visceral layer, except for
attachment to epididymis and spermatic
cord
• Parietal layer is adjacent to internal
spermatic fascia
• Small amount of fluid allows free
movement
• Tunica albuginea = tough fibrous outer
surface
• Mediastinum of testis = origin of fibrous
septa
• Right testicular vein  IVC, left vein 
renal artery
Epididymis
• Duct of epididymis = Convoluted
tube of smooth muscle of
posterior aspect of testes – moves
spermatozoa distally with
peristalsis and stereocilia
• Head superior expanded part
(lobules of 12-14 ductuli
efferentes)
• Appendices of epididymis =
remnant of mesonephric
(Wolffian) duct
• Body
• Tail
Ductus
Deferens
• Continuation of duct of
epididymis (from tail) –
ascends posterior to testis
and medial to epididymis
• Penetrates abdominal wall
via spermatic cord /
inguinal canal, crossing
external iliac vessels
• Crosses ureter, terminates
as the ampulla of ductus
deferens to join duct of
seminal gland to form
ejaculatory duct
• Artery to ductus deferens
arises from superior
vesical
Seminal Vesicles and
Ejaculatory Duct
• Seminal vesicle (gland) about 5cm-long glandular diverticulum
between fundus of bladder and rectum
• Does not store sperm
• Duct of seminal vesicles joins ampulla of ductus deferens
• Ejaculatory duct: 2.5cm long, slender tubes that pass through
prostate
• Alongside prostatic utricle
• Open on the verumontanum (seminal colliculus)
• Supplied by artery to ductus deferens
• Ductus deferens, seminal glands, ejaculatory ducts and
prostate innervated by sympathetic nervous system
(intermediolateral cell column T12-L2 via transverse lumbar
splanchnic nerves, hypogastric and pelvic nerve plexuses)
Prostate
• Fibrous capsule + visceral
layer of pelvic fascia =
prostatic sheath
• Connects with
puboprostatic ligaments
anteriorly
• Rectovesical septum
posterior
• Base (neck of bladder)
• Apex (urethral sphincter,
perineal muscles)
• Anterior surface
(rhabdosphincter /
external urethral
sphincter); Space of
Retzius / retropubic space
• Posterior surface
(ampulla of rectum)
• Inferolateral surface
(levator ani)
• Largest accessory gland of male system – 3
x 4 x 2cm (length/width/depth)
Divisions of prostate
• Lobes
• Isthmus (anterior lobe)
• Right and left lateral lobes
• Inferoposterior lobule (palpable in DRE)
• Inferolateral lobule (lateral to urethra)
• Median lobe – undergoes hypertrophy
• Superomedial lobule (surrounds ejaculatory duct
• Anteromedial lobule (proximal prostatic urethra)
• Zones
• Transition zone (5% of glandular tissue, around proximal urethra –
site of benign nodular hyperplasia)
• Central zone (around ejaculatory ducts, 20% of tissue)
• Peripheral zone (70% of tissue, most cases of prostatic
carcinoma)
• Prostatic ducts (20-30) open into
prostatic sinuses either side of
verumontanum (seminal colliculus)
• Prostatic utricle = remnant of
uterovaginal canal
• Corpora amylacea = inspissated
prostatic secretions that increase
with age and become calcified
• Prostatic arteries = branches of
inferior vesicle (some from internal
pudendal and middle rectal)
• Prostatic venous plexus drains into
internal iliac
Male Urethra
• Four parts: intramural, prostatic,
membranous, spongy
• Membranous
• Apex of prostate to bulb of penis via
external urethral sphincter
• Bulbourethral glands of Cowper lie
posterolateral to membranous urethra,
inside external urethral sphincter
• Spongy urethra in corpus spongiosum,
5mm in diameter
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Intrabulbar fossa in bulb of penis
Navicular fossa in glans
Urethral glans secrete mucus
Somatic innervation visa dorsal nerve of
penis (pudendal)
• Dorsal artery of penis supplies
membranous and spongy parts
Penis
• Erect in anatomical position, so dorsum faces anteriorly
when flaccid
• Three cylindrical cavernous bodies
• Paired corpora cavernosa dorsally (singular = corpus
cavernosum). Forma crura of the penis proximally,
separated by septum penis
• Corpus spongiosum
• Each covered in fibrous capsule, tunica albuginea
• Root of penis = attached part. Located in superficial
perineal pouch
• Crura = masses of erectile tissue. Each crus attached to
ischial ramus
• Bulb = enlarged posterior part. Penetrated by urethra
• Ischiocavernosus and bulbospongiosus muscles
• Suspensory ligament of penis (sling from symphysis)
• Fundiform ligament of penis (from linea alba, anterior
to symphysis)
• Buck’s fascia = deep fascia of the penis (continuation of
perineal fascia)
• Body is free part suspended from pubic symphysis. No muscular
tissue
• Glans = distal expansion of corpus spongiosum
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Corona of glans = proximal margin
Coronal sulcus = oblique groove overhung by corona
Covered by prepuce (foreskin)
Frenulum of prepuce = median fold
External urethral meatus near tip of glans
• Arterial supply: From internal pudendal
• Dorsal arteries of penis run in dorsal groove between corpora
cavernosa
• Deep arteries run in centre of corpora cavernosa
• Form helicine arteries of penis in erectile tissue
• Venous drainage: Dorsal vein of penis drains to prostatic venous
plexus
• Innervation: PSNS S2-S4 via pelvic splanchnic and pudendal