Chapter 5
Page 53
1. Describe the stages of palatal development
-It is formed from two separate embryonic structures: the primary palate and the secondary palate.
-Begins in the 5th week of prenatal development, within the embryonic period
-Three stages:
The formation of the primary palate
The formation of the secondary palate
Completion of the palate
2. What is the difference between the primary and secondary palate? To what does each give rise?
Primary Palate
5th week-6th week
intermaxillary segment
Fusion of 2 medially nasal processes
Extends inferiorly and deep to nasal pits of inside of stomodeum and develop into floor of nasal pits and septum
Gives rise to premaxillary portion of maxillar and becomes ant one third of final or definitive hard palate
Secondary Palate Formation
6th week-12th week
Bilatteral maxillary processes give rise to two palatal shelves
Fused palatal shelves from maxillary processes
Gives rise to posterior 2/3 of hard palate
Contains incisive foramen, max canines, and post teeth.
Also gives rise to soft palate and uvula
Median palatine raphe on the surface of mucosa and underneath median palatine suture on adult bone= line of fusion of palatal shelves
3. Explain the completion of the palate
Completion of Palate
Secondary meets post portion of primary and fuses
12th week three completely fused
Oral cavity separated from nasal cavity
Bone formation has already begun in the anterior hard palate by time palatial fusion is complete
4. What are the developmental disturbances that can occur with the formation of the palate and related tissues?
Cleft palate
Cleft Uvula
Bilateral cleft
Unilateral cleft of lip
5. Describe the formation of the nasal cavity and septum
Nasal forms at same time as palate
Part of respiratory
Nasal septum is too
9th week – vertical nasal septum
12th week- fuses with horizontally oriented final palate
Nasal and oral undergo different types of mucosa
Nasal septum determines orofacial form and grows 7 times its size between development and birth