Postnasal maturation of the human endolymphatic sac.
OBJECTIVE
The objective of this study was to trace the postnatal development of the human endolymphatic sac. The endolymphatic sac starts as a pouch-like structure during the fetal period in the human but later develops into a complex network of tubules in its mature form.


METHODS
Observational study.


METHODS
Light microscopic examination of the morphology of the endolymphatic sac in a population of temporal bones.


RESULTS
Examination of 28 temporal bones from 19 infants and children reveals that endolymphatic sac morphological maturation is usually completed in the first year of life, although it may occur as late as 4 years of age. There was good correlation of maturation levels between sides when pairs of temporal bones were evaluated. Immature pouch-like endolymphatic sacs may appear as late as 4 years of age.


CONCLUSIONS
Endolymphatic sac maturation to its adult tubular form is usually completed by the first year. This finding contrasts with other studies examining the growth of the endolymphatic sac to adult size after birth. Histological evidence suggests that the endolymphatic sac, although not morphologically mature by appearance, may still be participating at some level of functioning.
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Department of Otolaryngology, Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
D002675:Child, Preschool; D004712:Endolymphatic Sac / Q000166:cytology / Q000254:growth & development*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D019370:Observation; D013701:Temporal Bone / Q000473:pathology*