RT Book, Section
A1 Derkay, Craig S.
A1 Cunningham, Michael J.
A2 Rudolph, Colin D.
A2 Rudolph, Abraham M.
A2 Lister, George E.
A2 First, Lewis R.
A2 Gershon, Anne A.
SR Print(0)
ID 7034330
T1 Chapter 372. The Head, Face, and Neck
T2 Rudolph's Pediatrics, 22e
YR 2011
FD 2011
PB The McGraw-Hill Companies
PP New York, NY
SN 978-0-07-149723-7
LK accesspediatrics.mhmedical.com/content.aspx?aid=7034330
RD 2024/04/19
AB The  critical  period  of  cervicofacial  growth  and  differentiation  occurs  between  weeks  4  through  8  of  embryologic  development.1  The  beginning  of  this  stage  is  characterized  by  the  appearance  of  the  frontonasal  process—the  precursor  of  the  forebrain  and  upper  face—with  development  soon  thereafter  of  the  optic  and  otic  vesicles;  the  nasal  placodes;  the  primitive  mouth,  or  stomodeum;  and  five  ridges  on  the  ventrolateral  surface  of  the  embryonic  head,  which  is  known  as  the  branchial  system.  Many  of  the  symmetrically  paired  skeletal  and  neuromuscular  structures  of  the  head  and  neck  arise  from  the  first  (mandibular),  second  (hyoid),  third  (pharyngeal),  and  fourth  (laryngeal)  arches  of  this  fetal  branchial  system  (Table  372-1).  The  skull,  facial,  and  neck  bones  have  begun  to  ossify  by  the  end  of  the  eighth  fetal  week,  which  coincides  with  a  recognizable  human  embryonic  face  with  easily  discernible  ears,  eyelids,  cheeks,  nose,  and  upper  and  lower  lips.