title: Development of the stapedius muscle canal and its possible clinical consequences.
abstract: OBJECTIVE
  To study the development of the stapedius muscle canal in human embryos and foetuses.
  
  
  METHODS
  46 temporal bones with ages between 9mm and new-borns were studied. The preparations were dyed using Martins' trichrome technique.
  
  
  RESULTS
  Two areas of different embryological origin form the stapedius muscle canal, which contains this muscle and the facial nerve. On the otic capsule, at 11 weeks an extension starts to grow from its caudal part, which moves outwards and near to Reichert's cartilage, forming the footplate and internal wall. The pyramidal eminence comes from the mesenchyme that surrounds the muscle, forming a partition to separate it from the laterohyale portion of Reichert's cartilage. Extensive connections are observed in its development between bone marrow and mesenchyme. At 35 weeks the muscle and nerve start to separate by means of a bony partition. If this partition does not form, there is going to be a dehiscence that could cause peripheral nerve pathology due to the repeated contraction of the muscle, or the dissemination of infections from middle ear.
  
  
  CONCLUSIONS
  During the development of the stapedius muscle canal the presence of dehiscences between the facial nerve and the muscle may have clinical repercussions.
authors.affiliation: Department of Human Anatomy and Histology, School of Medicine, University of Zaragoza, C/ Domingo Miral, s/n, 50009 Zaragoza, Spain. aicisner@unizar.es
authors.forename: Ana
authors.initials: A
authors.lastname: Cisneros
authors.forename: Jaime R Whyte
authors.initials: JR
authors.lastname: Orozco
authors.forename: Jesús Angel Obón
authors.initials: JA
authors.lastname: Nogues
authors.forename: Carmen Yus
authors.initials: CY
authors.lastname: Gotor
authors.forename: Ana Whyte
authors.initials: AW
authors.lastname: Orozco
authors.forename: Miguel Angel Crovetto
authors.initials: MA
authors.lastname: de la Torre
authors.forename: Arturo Vera
authors.initials: AV
authors.lastname: Gil
mesh_terms: D047108:Embryonic Development / Q000502:physiology; D005260:Female; D047109:Fetal Development / Q000502:physiology; D006801:Humans; D008297:Male; D024510:Muscle Development / Q000502:physiology*; D012494:Sampling Studies; D013198:Stapedius / Q000033:anatomy & histology / Q000196:embryology*