Male reproductive system

Gross Anatomy

Arteries

Blood flow in male reproductive system

Scrotum

Coverings:

  • Skin (dark, rugae, thin)
  • Superficial fascia (no fat)
  • Darto’s muscle

NB: When cold, Darto’s muscle contracts skin, scrotum wrinkles and therefore reduces surface area for heat loss

Scrotum divided internally by Darto’s fascia into left and right, externally seen as scrotal raphe

Location: Inferior and posterior to penis

Contents: Testis, epididymis, spermatic cord

Blood supply: Anterior scrotal, posterior scrotal, cremasteric

Venous: Scrotal veins drain into external pudendal veins

Nerves:

  • Genitofemoral nerve – genital branch
  • Ilioinguinal nerve – anterior scrotal nerve
  • Pudendal nerve – posterior scrotal nerve
  • Posterior femoral cutaneous – perineal branch

Lymphatics: Superficial inguinal nodes

Testis

Coverings:

Image result for testis covering layers covering the testis

Blood supply: Testicular, scrotal, deferential, cremasteric

Venous: Right testicular vein drains into IVC, left drains into left renal vein

Nerves: Testicular plexus

Lymphatics: Lumbar nodes

Clinicals:

  • Orchitis – inflammation of testis
  • Hydrocele – excess fluid in TV
  • Hematocele – blood in TV
  • Varicocele – venous plexus dilated
  • Spermatocele – collection of fluid in epididymis
  • Vasectomy – vas deferens ligated and cut
  • Distention of scrotum – indirect hernia

Spermatic cord

Forms at deep inguinal ring, enters scrotum via superficial inguinal ring, ends at posterior border of testis

Coverings:

  • External spermatic fascia (aponeurosis of external oblique)
  • Cremasteric muscle and fascia (internal oblique)
  • Internal spermatic fascia (transversalis fascia)

Contents:

  • Vas deferens
  • Lymph vessels
  • Testicular artery
  • Cremasteric vessels
  • Deferential artery
  • Genital nerve

Clinicals:

  • Hydrocele of cord
  • Torsion of spermatic cord – Surgical emergency, twists on itself, occludes testicular artery and venous drainage leading to necrosis
  • Cremasteric reflex

Image result for cremasteric reflex

Penis

parts of the penis

Coverings:

  • Skin – thin, dark, prepuce covers glans
  • Deep fascia of penis – continuation of perineal fascia
  • Tunica albuginea

Support:

  • Suspensory ligament – connects erectile bodies to pubic symphysis
  • Fundiform ligament

Image result for fundiform and suspensory ligaments of penis

Blood supply: Dorsal, deep and bulb of penis arteries

Venous: 

  • Deep dorsal vein – drains to prostatic venous plexus
  • Superficial dorsal vein – drains to superficial external pudendal vein

Nerves:

  • Paired dorsal nerve of penis (pudendal nerve) – sensory and sympathetic
  • Cavernous nerves (prostatic nerve plexus) – parasympathetic, responsible for the vascular changes which cause erection

Lymphatics: Deep inguinal nodes (glans penis), superficial inguinal nodes

Clinicals:

  • Hypospadias – Born with urethra opening on ventral aspect
  • Circumcision – surgical excision of prepuce, glans exposed
  • Impotence – inability to achieve erection
  • Erectile dysfunction – inability to maintain erection
  • Priapism – Persistent erection, blood trapped in erectile tissue, can lead to scarring or erectile dysfunction

Prostate gland

Position: Surrounds prostatic urethra, inferior to bladder neck

Relations:

  • Anterior – Pubic symphysis
  • Posterior – Ampulla of rectum
  • Superior – Neck of bladder
  • Inferior – External urethral sphincter
  • Inferolateral – levator ani muscles

Blood supply: Prostatic artery (from internal iliac), middle rectal, internal pudendal

Venous: Prostatic venous plexus – drains to internal iliac veins

Nerves: Inferior hypogastric plexus

Lymphatics: Internal iliac, sacral nodes

Clinicals: 

  • Benign prostatic hyperplasia – enlargement of prostate with no malignancy, urinary frequency increases as it compresses bladder and urethra
  • Cancer – spread via blood and lymph to IVC, vertebral column and pelvis

Seminal vesicle

Vas deferens combines with seminal vesicle duct to form ejaculatory duct which drains into prostatic urethra

Position: Between bladder fundus and rectum/rectovesical pouch

Relations:

  • Anterior – Bladder fundus, ureter
  • Posterior – Rectum
  • Inferior – Prostate and ejaculatory duct
  • Medial – Vas deferens
  • Lateral – Prostatic venous plexus

Blood supply: Inferior vesicle, middle rectal, internal pudendal

Nerves: Inferior hypogastric plexus

Lymphatics: External and internal iliac lymph nodes

Clinicals: Seminal gland abscess – may rupture, pus enters peritoneal cavity

Vas deferens

Continuation of epididymis in spermatic cord

Course:

  • From tail of epididymis
  • Ascends posterior to testis
  • Through spermatic cord
  • Penetrate abdominal wall via inguinal canal
  • Crosses external iliac vessels
  • Turns medial between bladder and urethra
  • Joins duct of seminal vesicle to form ejaculatory duct

Blood supply: Deferential artery

Venous: Testicular vein, prostate venous plexus

Lymphatics: External iliac

Clinicals: Vasectomy – male sterilization

These are summarized notes from various sources, mainly TeachMeAnatomy and Wikipedia