title: Development of the penis during the human fetal period (13 to 36 weeks after conception).
abstract: OBJECTIVE
  We analyzed the development of the area of the penis and erectile structures (corpora cavernosa and corpus spongiosum) and the thickness of the tunica albuginea during the fetal period (13 to 36 weeks after conception) in humans to establish normative patterns of growth.
  
  
  METHODS
  We studied 56 male human fetuses at 13 to 36 weeks after conception. We used histochemical and morphometric techniques to analyze the parameters of total penile area, area of corpora cavernosa, area of corpus spongiosum, and thickness of tunica albuginea in the dorsal and ventral regions using ImageJ software (National Institutes of Health, Bethesda, Maryland).
  
  
  RESULTS
  Between 13 and 36 weeks after conception the area of the penis varies from 0.95 to 24.25 mm2. The area of the corpora cavernosa varies from 0.28 to 9.12 mm2, and the area of the corpus spongiosum varies from 0.14 to 3.99 mm2. The thickness of the tunica albuginea varies from 0.029 to 0.296 mm in the dorsal region and from 0.014 to 0.113 mm in the ventral region of the corpora cavernosa.
  
  
  CONCLUSIONS
  We found a strong correlation between the total penile area, corpora cavernosa and corpus spongiosum with fetal age (weeks following conception). The growth rate was more intense during the second trimester (13 to 24 weeks of gestation) compared to the third trimester (25 to 36 weeks). Tunica albuginea thickness also was strongly correlated with fetal age and this structure was thicker in the dorsal vs ventral region.
authors.affiliation: Urogenital Research Unit, State University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Carla B M
authors.initials: CB
authors.lastname: Gallo
authors.forename: Waldemar S
authors.initials: WS
authors.lastname: Costa
authors.forename: Angelica
authors.initials: A
authors.lastname: Furriel
authors.forename: Ana L
authors.initials: AL
authors.lastname: Bastos
authors.forename: Francisco J B
authors.initials: FJ
authors.lastname: Sampaio
mesh_terms: D002102:Cadaver; D005865:Gestational Age; D006801:Humans; D008297:Male; D010413:Penis / Q000196:embryology / Q000254:growth & development*; D012016:Reference Values
keywords: MRI; WPC; fetus; growth; magnetic resonance imaging; penis; week post conception