Male Reproductive Anatomy : Mnemonics

Penile Layers

Mnemonic: ABCD (from inside to outside)

1. Albuginea (tunica albuginea): Envelopes 3 corporal bodies (2 cavernosa and 1 spongiosum)

2. Buck’s fascia: Separates corpora cavernosa from corpus spongiosum; separates superficial and deep dorsal veins of the penis

• Corpora cavernosa
  • Forward continuation of crura
• Corpus spongiosum:
  • Continuation of bulb of penis
  • Encloses spongy/penile urethra
• Suspensory ligament: attachment to pubic bone maintains penile position during erection

3. Colle’s fascia: Continuous with Scarpa’s fascia of abdomen and Dartos fascia of scrotum

• Fundiform ligament: It springs from the lower part of the linea alba and splits into 2 lamellae, which enclose the proximal part of the body of penis and after that connect on its urethral aspect together with the septum of scrotum.

4. Dermis (skin)

Nerve Supply of Penis

Sensory and Motor:

Mnemonic: PID

1. Motor: Pudendal nerve (S2-S4)
2. Sensory: Ilio-inguinal nerve, Dorsal nerve of penis

Autonomic innervation:

1. Parasympathetic (muscle relaxation) via S2-S4: Pointing (erection)
2. Sympathetic (muscle contraction) via T11-L2: Shooting (ejaculation)

Scrotum and Testis Layers

Mnemonic: Some Dirty Englishmen Called It Testis (Outside to Inside)

Layer	Derived from anterior abdominal wall
1. Skin	Skin
2. Dartos muscle/fascia	Superficial fascia
3. External spermatic fascia	External oblique aponeurosis
4. Cremasteric muscle/fascia	Internal oblique
5. Internal spermatic fascia	Transversalis fascia
6. Tunica vaginalis (parietal and visceral)	Peritoneum
7. Tunica albuginea – septates testis into lobules

Since the testes are originally retroperitoneal organs, the lymphatic drainage is to the lumbar and para-aortic nodes, along the lumbar vertebrae. This is in contrast to the scrotum, which drains into the nearby superficial inguinal nodes.

Carcinomas confined to testes thus never result in inguinal lymphadenopathy and are surgically removed via and inguinal incision.

Male Urethra

Mnemonic: Pet My Beautiful Pig (Proximal to Distal)

Portion	Segment	Length	Features
1. Posterior (lined by transitional columnar epithelium)	Prostatic	3 cm	Widest and most dilatable
– Iliac lymph nodes	Membranous	2 cm	Shortest, narrowest and least dilatable
– Injury = Deep extravasation of urine (extraperitoneal/into deep perineal pouch)
2. Anterior (lined by pseudostratified columnar epithelium; distal-most portion by squamous epithelium)	Bulbar
– Inguinal lymph nodes	Penile/Spongy	16 cm	Longest
– Injury = Superficial extravasation of urine (intraperitoneal/into superficial perineal pouch)

Spermatic Cord

Spermatic Cord : Mnemonics

Sperm Ejaculation Pathway

Mnemonic: SEVEN UP

1. Seminiferous tubules
2. Epididymis
3. Vas deferens
4. Ejaculatory ducts
5. None
6. Urethra
7. Penis

Derivatives of Embryonic Genital Structures

Embryonic structure	Male	Female
Indifferent gonad	Testis	Ovary
Cortex		Ovarian follicles
Medulla	Seminiferous tubules Rete testis	Medulla Rete ovarii
Gubernaculum	Gubernaculum testis	Ovarian ligament Round ligament of uterus
Mesonephric tubules	Ductuli effernetis Paradidymis Abberant ductules Ductus epididymis Ductus deferens Ureter, pelvis, calyces and collecting systems	Epoophoron Paraoophoron Duct of epoophoron Duct of paraophoron Ureter, pelvis, calyces and collecting systems
Mesonephric duct	Appendix of epididymis Ejaculatory duct & seminal vesicle
Paramesonephric duct	Appendix of testis Prostatic utricle	Hydatid of Morgagni Fallopian tubes Uterus Vagina (upper)
Genital tubercle	Penis	Vestibule Clitoris
Urogenital folds	Ventral (under) aspect of penis – penile urethra	Labia minora
Labioscrotal swellings	Scrotum	Labia majora