title: Development of the rat larynx: a histological study.
abstract: OBJECTIVE
  To evaluate and describe the cartilaginous and muscular development of the rat larynx.
  
  
  METHODS
  Histologic evaluation.
  
  
  METHODS
  The larynges of Sprague Dawley rats of embryonic day (E) 13, 15, 17, 19, 21, postnatal day 0, 14, and adult of 250 gm were collected. Four larynges of each age were harvested, cut into 15-μm serial sections, stained with hematoxylin and eosin, and evaluated under light microscopy. Representative digital images were recorded and evaluated at the preglottic (supraglottic in humans), glottic, and postglottic (subglottic in humans) levels.
  
  
  RESULTS
  Brachial arches were observed at E13. At E17, immature structures of the larynx, including skeletal muscle, cartilage, and the lumen were identifiable. Chondrification and muscle formation were clearly seen by E19. The muscular and cartilagenous components of the larynx were well established by E21. During the span between birth and adult maturation, the size of the larynx increased from a height of 1.10 mm to 2.90 mm, and from a width of 1.80 mm to 5.40 mm, and from a length of 1.38 mm to 4.77 mm in the stained section. Although developed at E21, the laryngeal structures continued to grow by approximately 30%.
  
  
  CONCLUSIONS
  Rat laryngeal development parallels that in mice and humans. In the rat, at E17 immature structures of the larynx are identifiable, they are well developed at birth and grow by approximately 30% into adulthood. Understanding the chronology and morphology of the embryogenesis of the rat laryngeal musculature is essential and will allow for further evaluation of the embryologic innervation of these muscles.
authors.affiliation: Department of Cell Biology and Anatomy, New York Medical College, Valhalla, New York, U.S.A.
authors.forename: Opeyemi
authors.initials: O
authors.lastname: Alli
authors.forename: Craig
authors.initials: C
authors.lastname: Berzofsky
authors.forename: Sansar
authors.initials: S
authors.lastname: Sharma
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Pitman
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D005260:Female; D005500:Follow-Up Studies; D005931:Glottis / Q000166:cytology / Q000196:embryology / Q000254:growth & development; D007821:Laryngeal Muscles / Q000166:cytology / Q000196:embryology / Q000254:growth & development; D007830:Larynx / Q000166:cytology* / Q000196:embryology / Q000254:growth & development*; D011247:Pregnancy; D011270:Pregnancy, Animal; D051381:Rats
keywords: Embryogenesis; development; larynx; rat; recurrent laryngeal nerve