title: A comparative morphologic and morphometric study about geniculate ganglion development in man and in rat.
abstract: CONCLUSIONS
  Human-rat geniculate ganglion (GG) have multiple origins: (1) An initial proximity (20 μm) to the endocranial foramen of the IAM, suggests neural crest induction; and (2) The influence of epibranchial placodes: the tensor tympani muscle (TTM) and the otic apical coil.
  
  
  OBJECTIVE
  This study was undertaken to determine the comparative development of human-rat GG.
  
  
  METHODS
  A light microscopic study of the GG in human material obtained from spontaneous abortions at 9, 13, 14, 17, 18, and 30 weeks, and one neonate was done. This study examined Webster rat embryos and a post-natal series. Specimens were fixed in Bouin fluid, embedded in paraffin, cut, and stained with H&E. The histomorphometric data were obtained with image analysis software.
  
  
  RESULTS
  The human fetus of 9 weeks presents two neuronal groups in the VII nerve: one near (20 μm) the IAM endocranial foramen, foraminal, and the other, tympanic. Neonate GG is located between the TTM and the cochlear apex (inwards). In the 16 day old rat embryo GG is placed within a canal containing the stapedial artery. In the adult rat the GG and the stapedial artery are placed within the IAM.
authors.affiliation: a Otorhinolaryngology Department, School of Medicine , University of the Basque Country , Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Sánchez-Del-Rey
authors.affiliation: a Otorhinolaryngology Department, School of Medicine , University of the Basque Country , Spain.
authors.forename: José Maria
authors.initials: JM
authors.lastname: Sánchez-Fernández
authors.affiliation: b Otorhinolaryngology Service , Basurto University Hospital , Bilbao , Spain.
authors.forename: Arantza
authors.initials: A
authors.lastname: Ibargutxi
authors.affiliation: a Otorhinolaryngology Department, School of Medicine , University of the Basque Country , Spain.
authors.forename: Agustin
authors.initials: A
authors.lastname: Martinez-Ibargüen
authors.affiliation: a Otorhinolaryngology Department, School of Medicine , University of the Basque Country , Spain.|b Otorhinolaryngology Service , Basurto University Hospital , Bilbao , Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Santaolalla
mesh_terms: D000818:Animals; D001699:Biometry; D047109:Fetal Development; D005830:Geniculate Ganglion / Q000196:embryology*; D006801:Humans; D051381:Rats
keywords: Neural crest induction; apoptosis; cranial base ossification; geniculate ganglion development; neuronal migration