MALE EXTERNAL GENITALIA MALE URETHRA S-IV RM26
LEARNING OBJECTIVES
 At the end of lecture student should know:
 Gross anatomy of male external genitalia
 Their arterial, venous drainage & nerve supply
 Anatomy of male urethra. Its arterial, venous drainage & nerve supply
GENERAL CONSIDERATION
 The male external genital organs include:
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The penis
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The scrotum
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The testis
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The epididymis
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The spermatic cord
THE PENIS
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Organ of copulation
cylindrical in shape (flaccid condition)
triangular in shape with rounded angles (erect condition)
suspended from the front and sides of the pubic arch
containing the greater part of the urethra
Provide common outlet for urine & semen
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STRUCTURE OF THE PENIS
composed of three cylindrical masses
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Paired corpora cavernosa penis(lateral)
Sigle corpus cavernosum urethræ (median)
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CORPORA CAVERNOSA PENIS
Anterior three-fourths lie in intimate apposition with one another,
Posterior one-fourth diverge & form two crura, which are firmly connected
to the rami of the pubic arch
each crus presents a slight enlargement, Just before it meets its fellow, the
bulb of the corpus cavernosum penis.
Beyond this point the crus merges into the corpus cavernosum proper
CORPORA CAVERNOSA PENIS
The corpora cavernosa penis are surrounded by a strong fibrous
envelope Tunica albuginea consisting of:
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Superficial fibers
– longitudinal
– form a single tube
– encloses both corpora
Deep fibers
– Circular
– Enclose each corpus separately
– Form septum of the penis (in median plan)
• Thick and complete behind
• Imperfect in front
• Consists of a series of vertical bands (the teeth of a comb)
therefore named the septum pectiniforme.
CORPUS CAVERNOSUM URETHRÆ
Aka corpus spongiosum
Cylindrical in form
Contains the urethra
Lies in a groove on the corpora cavernosa penis
Anteriorly, it is expanded to form the glans penis
Posteriorly, it is expanded to form the urethral bulb
Lies in apposition with the inferior fascia of the urogenital diaphragm, from
which it receives a fibrous investment.
REGIONS OF PENIS
For descriptive purposes it is divided in to:
• the Root
• the Body
• the Extremity
THE ROOT OF THE PENIS
(RADIX PENIS)
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It is triradiate in form
lies in the perineum between the inferior fascia of the urogenital
diaphragm and the fascia of Colles
it is bound to the symphysis pubis by the
– fundiform ligaments
– Suspensory ligaments
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consisting of :
– Two crura (one on either side)
– covered by the ischiocavernosus
– the urethral bulb (median)
– covered by the bulbocavernosus
THE BODY (CORPUS PENIS)
Extends from the root to the ends of the corpora cavernosa penis
Ensheathed by fascia, which is continuous
– Above with the fascia of scarpa
– Below with the dartos tunic of the scrotum and the fascia of colles.
On the upper surface a shallow groove lodges the deep dorsal vein of the
penis
On the under surface deeper and wider groove contains the corpus
cavernosum urethræ.
THE EXTREMITY
The expanded anterior end of the corpus cavernosum urethræ
Is formed by the glans penis
Separated from the body by the constricted neck, which is overhung by the
corona glandis.
THE INTEGUMENT COVERING OF THE PENIS
Is very thin
Dark color
Loosely connected with the deeper parts of the organ
Absence of adipose tissue
At the root of the penis it is continuous with the skin of pubes, scrotum, and
perineum
At the neck it is folded to form prepuce or foreskin
On the undersurface of the glans, a median fold, the frenulum
The potential space between the glans & perpuce is, preputial sac
Preputial glands
– On corona glandis & on neck of the penis
– Secrete smegma(sebaceous)collects in preputial sac
ARTERIES OF THE PENIS
The internal pudendal artery gives off:
• The deep artery of the penis
• Runs in the corpus cavernosum
• Breaks up in helicine arteries(spiral)
• The dorsal artery of the penis
• Runs on the dorsum
• Supply distal corpus spongiosum,prepuce & frenulum
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The artery of the bulb of the penis
• Supply bulb & proximal corpus
Femoral artery
• Superficial external pudendal artery
• Supply skin & facsia
VIENS OF THE PENIS
Superficial dorsal vein
• Right branch
Drain into superficial external pudendal veins
• Left branch
Deep dorsal vein drain in to prostatic plexus
LYMPHATIC DRAINAGE
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From the glans
– Deep inguinal lymph nodes
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Rest of the penis
Deep inguinal lymph nodes
NERVE SUPPLY
Sensory nerve supply
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Dorsal nerve of the penis
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Ilioinguinal nerve
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Muscular supply by perineal br. Of pudendal nerve
SCROTUM
1. “Medial pendant pouch of loose skin & superficial fascia” (Gray’s)
2. Raphe (Gr. “seam” or “suture”): Superficial division between compartments
3. Left side lower than right
SCROTUM
4. Dartos muscle (lies in fascia)
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Temperature sensitive response
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hot = relax
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cold = contract
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Right & left compartments
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Testis, epididymis, tunica vaginalis in each
LAYERS OF SROTUM
Layers, beginning superficially
– Superficial fascia
• Skin & tunica dartos
– Colle’s fascia
• Membranous layer of superficial fascia
• Continuous over penis & scrotumc
– External spermatic fascia: derived from
1. Transversus abdominis
2. Internal oblique muscle
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LAYERS OF SROTUM
Cremasteric fascia: derived from
1. Transversus abdominis
2. Internal oblique muscle
Internal spermatic fascia: derived from
 Transversalis muscle