Penis and scrotum
General
Anatomy of penis

Authors: Antonio Cubilla, M.D., Alcides Chaux, M.D. (see Authors page)

Revised: 28 March 2018, last major update May 2010

Copyright: (c) 2002-2018, PathologyOutlines.com, Inc.

PubMed Search: Anatomy[TI] penis[TIAB]

Cite this page: Cubilla, A., Chaux, A. Anatomy of penis. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/penscrotumanat.html. Accessed September 22nd, 2018.
Definition / general
  • 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
  • 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) 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
    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 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, nonkeratinized and squamous epithelium

    Frenulum:
    • Fibrous band of tissue attaching foreskin to ventral glans

    Coronal sulcus:
    • Narrow and circumferential cul de sac (in noncircumcised) behind glans corona; area of insertion of dartos and Buck 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
  • Superficial inguinal nodes (site of 1 - 3 sentinel nodes), deep inguinal, external iliac and internal iliac (pelvic nodes)
Periurethral glands
  • Cowper (bulbourethral) glands: mucinous acinar structures deep at level of membranous urethra
  • Intraepithelial glands (Morgagni lacunae): one layer cylindrical intraepithelial glands
  • Littre glands: tubuloacinar mucinous glands present along entire length of corpus spongiosum
Miscellaneous
  • 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 (see image below, Arch Pathol Lab Med 2000;124:1080)
  • Skin covering of penis is thin, stratified squamous epithelium, loosely connected to deeper parts of organ; nonkeratinizing at glans penis; keratinized after circumcision
  • Skin at root of penis is continuous with skin over scrotum and perineum
Drawings

Images hosted on PathOut server:

Transverse sections



Images hosted on other servers:

Compartments

Local anatomy

Arteries


Veins

Urethra

Corpora cavernosa

Transverse sections


Meatus

Glans

Cut section

Shaft cross section

Gross images

Images hosted on other servers:

Mucosal and wrinkled portion of foreskin

Cross section

Microscopic (histologic) images

Images hosted on other servers:

Transverse sections

Penile urethra

Body / shaft: longitudinal section

Body / shaft: Buck fascia


Foreskin: lamina propria and dartos

Glans: outer, middle and inner layer

Corpora cavernosa: microanatomy

Corpus spongiosum:
vascularized
tissue with
adjacent urothelium

Molecular / cytogenetics images

Images hosted on other servers:

Smear from postcoital penile swabbing