RT Book, Section
A1 Suurna, Maria V.
A2 Lalwani, Anil K.
SR Print(0)
ID 55766281
T1 Chapter 11. Congenital Nasal Anomalies
T2 CURRENT Diagnosis & Treatment in Otolaryngology—Head & Neck Surgery, 3e
YR 2012
FD 2012
PB The McGraw-Hill Companies
PP New York, NY
SN 978-0-07-162439-8
LK accesssurgery.mhmedical.com/content.aspx?aid=55766281
RD 2024/04/18
AB Nasal  development  occurs  during  weeks  4  through  10  of  gestation.  Migrating  neural  crest  cells  populate  the  frontonasal  prominence,  one  of  five  facial  prominences,  and  form  the  nasal  or  olfactory  placodes.  These  placodes  appear  as  convex  thickenings  on  the  surface  ectoderm  of  the  frontonasal  prominence.  A  central  depression  deepens  in  the  placodes  to  form  the  primitive  nasal  pit.  Mesenchymal  proliferation  during  the  5th  week  around  the  nasal  placodes  allows  the  horseshoe-shaped  medial  and  lateral  nasal  prominences  to  develop  and  fuse  to  form  the  nostrils.  The  nasal  pits  grow  toward  the  oral  cavity  and  develop  into  the  early  nasal  fossae.  The  nasobuccal  membrane  separates  the  nasal  cavities  from  the  oral  cavity.  This  membrane  subsequently  disappears,  allowing  for  communication  of  the  nasal  cavities  with  the  oral  cavity,  forming  the  primitive  posterior  nasal  choanae.  The  nasomedial  process  gives  rise  to  part  of  the  nasal  septum  and  the  medial  crus  of  the  lower  lateral  alar  cartilage.  The  nasolateral  process  develops  into  the  external  wall  of  the  nose,  nasal  bones,  upper  lateral  cartilage,  alae,  and  lateral  crus  of  the  lower  lateral  cartilage.  The  apex  and  dorsum  of  the  nose  develop  from  the  frontonasal  process  (Figure  11–1).