General
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• Suspended from front and sides of pubic arch, contains majority of urethra
• There are 3 main parts: proximal root, middle body (corpus or shaft) and the distal glans (head)
• Orientation: the upper surface is termed dorsal, the undersurface is termed ventral

Penile shaft / middle body
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• Composed of three cylindrical masses of cavernous erectile tissue (specialized venous sinuses of variable diameter and widely interconnected) bound together by fibrous tunica albuginea
  
  Penile (Buck’s) fascia:
  
  • Loose connective tissue located between dartos layer of the shaft and tunica albuginea
  • Extends from penile root to coronal sulcus
  • Contents are small blood vessels, penile dorsal veins, nerve bundles and adipocytes
  
  Dartos layer:
  
  • Smooth discontinuous muscle layer extending from homologous scrotal layer
  • Extends throughout entire shaft between dermis and penile fascia
  • In 50%, dartos layer reflects itself over the coronal sulcus and then continues to foreskin
  • In other 50%, dartos layer continues directly to foreskin
  
  Tunica albuginea:
  
  • Dense fibrous membrane encasing and separating dorsal corpora cavernosa and ventral corpus spongiosum
  • Extends from penile root to tips of corpora cavernosa
  
  Corpora cavernosa:
  
  • Two lateral masses of erectile tissue that form bulk of penis; posterior portions are called crura and connect to pubic arch
  • Contains c-kit / CD117+ interstitial cells, similar to those in gut (J Sex Med 2007;4:66)
  
  Corpus spongiosum:
  
  • Median mass of erectile tissue that contains most of urethra
  
  Male urethra:
  
  • Divided into 3 portions: prostatic urethra (proximal, surrounded by prostate, contains urothelium), membranous urethra (from lower pole of prostate to bulb of corpus spongiosum, stratified or ciliated pseudostratified columnar epithelium) and penile / distal urethra (passes through corpus spongiosum, stratified or ciliated pseudostratified columnar epithelium)
  • Length ranges from 15 to 29 cm (Int Braz J Urol 2008;34:451)
  • Layers are surface columnar epithelium and basal stratified or pseudostratified epithelium
  • Contains occasional PSA+ glands (Hum Pathol 2002;33:905)
  • Penile urethra contains plasma cells, T lymphocytes and macrophages; epithelium contains IgA secretory component and dendritic cells; protect against ascending infections (Am J Pathol 1995;147:155)

Distal penis
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Glans:

• Conical cup covering distal end of penile shaft
• Portion distal to coronal sulcus
• Layers are squamous epithelium, lamina propria, corpus spongiosum, tunica albuginea and corpora cavernosa

Glans coronal:

• At base of glans, slightly elevated circumferential rim
• May contain small papillae over its free border (erroneously mistaken for Tyson’s glands, which are absent in humans)

Meatus urethralis:

• Urethral opening
• Usually at central ventral glans penis
• Vertical cleft, related to frenulum (BJU Int 2007;100:161)

Fossa navicularis:

• Terminal dilated portion of penile urethra, contains stratified, non-keratinized and squamous epithelium

Frenulum:

• Fibrous band of tissue attaching foreskin to ventral glans

Coronal sulcus:

• Narrow and circumferential cul de sac (in non-circumcised) behind glans corona; area of insertion of dartos and Buck’s fascia

Foreskin:

• Skin folded on itself covering the glans (clitoris in females)
• In normal males, long foreskins cover the meatus and glans is not visible
• Layers are inner squamous epithelium, lamina propria, dartos layer and preputial skin
• In Chinese study, incidence of completely retractile foreskin increased from 0% at birth to 42% in adolescence; phimosis rate decreased with age from 99.7% to 7% (World J Pediatr 2009;5:312)

Regional lymph nodes
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• Superficial inguinal nodes (site of 1-3 sentinel nodes), deep inguinal, external iliac and internal iliac (pelvic nodes)

Periurethral glands
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• Cowper’s (bulbourethral) glands: mucinous acinar structures deep at level of membranous urethra
• Intraepithelial glands (Morgagni’s lacunae): one layer cylindrical intraepithelial glands
• Littre’s glands: tubuloacinar mucinous glands present along entire length of corpus spongiosum

Miscellaneous
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• Penile glycogenated epithelial cells indicate recent vaginal intercourse (Am J Clin Pathol 1985;84:524)
• Penile swabs after recent vaginal intercourse almost always contain female cells identifiable by FISH (image, Arch Pathol Lab Med 2000;124:1080)
• Skin covering of penis is thin, stratified squamous epithelium, loosely connected to deeper parts of organ; non-keratinizing at glans penis; keratinized after circumcision
• Skin at root of penis is continuous with skin over scrotum and perineum

Drawings
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Compartments

Local anatomy

Arteries

Veins

Urethra

Meatus

Glans

Cut section

Shaft cross section

Various images

Gross images
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Mucosal and wrinkled portion of foreskin

Cross section

Micro images
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Transverse sections

Penile urethra

Longitudinal section

Buck's fascia

Microanatomy

Drawing

Vascularized tissue with adjacent urothelium

Lamina propria and dartos

Outer, middle and inner layer

Intraepithelial glands

Littre’s glands

Virtual slides
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Cross section

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