title: Morphometric study on the anatomy of the fetal cricoid cartilage and comparison between its inner diameter and endotracheal tube sizes.
abstract: OBJECTIVE
  The high incidence of respiratory disorders is one of the main problems in perinatal medical care. With the increased use of intubation, the incidence of laryngeal injury causing stenosis has also increased. The principal constriction point in the infant's larynx is the midcricoid area. We sought to provide detailed morphometric data on the anatomy of the cricoid cartilage and its relationship with growth and body characteristics of fetuses at 5 to 9 months of gestational age.
  
  
  METHODS
  Nineteen larynges obtained from 17 stillborn infants and 2 newborn infants ranging in gestational age from 5 to 9 months were studied. Measurements of the cricoid cartilage were made with a millimeter-graded caliper.
  
  
  RESULTS
  Weight was the variable most correlated with cricoid measurements. The cricoid lumen configuration showed an almost elliptic shape and did not change with gestational age. The mean inner subglottic cricoid area was 19.27 +/- 9.62 mm2 and was related to weight and body surface area. Cricoid growth was more pronounced at the outer portion of the cartilage.
  
  
  CONCLUSIONS
  The cricoid lumen configuration was elliptic, and its mean area was smaller than that of available endotracheal tubes. This lumen area was most influenced by weight and height.
authors.affiliation: Department of Otorhinolaryngology, Clinicas Hospital, University of São Paulo School of Medicine, São Paulo, Brazil.
authors.forename: Leila F R
authors.initials: LF
authors.lastname: Lima
authors.forename: Luciana M
authors.initials: LM
authors.lastname: Nita
authors.forename: Victor E S
authors.initials: VE
authors.lastname: Campelo
authors.forename: Rui
authors.initials: R
authors.lastname: Imamura
authors.forename: Domingos H
authors.initials: DH
authors.lastname: Tsuji
mesh_terms: D002102:Cadaver; D003413:Cricoid Cartilage / Q000033:anatomy & histology* / Q000254:growth & development; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D009929:Organ Size; D014132:Trachea / Q000033:anatomy & histology* / Q000254:growth & development