Development of Palate

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Development of Palate Powered By Docstoc
					  Development
    of Soft &
  Hard Palate
Dr. Muhammad Rafique
    Anatomy, DIMC
             Objectives
Know the development of face
Have knowledge of development of
 primary palate
Mention the development of Secondary
 palate
Discuss the development of Hard Palate
Describe the development of Soft Palate
Know developmental anomalies of
 Palate
               Development of face
Development of
  face requires five
  prominences
One Fronto-nasal
  Prominence
Two Maxillary
  Prominence
Two Mandibular
  Prominence
           Development of Palate
Development of palate
  depends upon the
  proper development
  of frontonasal
  prominence and
  maxillary
  prominences and
  than proper fusion
  of all three
  prominences
             Development of Palate
The palate develops in two
   stages:
1. Development of a primary
   palate
2. Development of a secondary
   palate
Palatogenesis begins in the sixth
   week; however, development
   of the palate is not completed
   until the 12th week. The
   critical period of palate
   development is from the end
   of the sixth week until the
   beginning of the ninth week.
                  Primary Palate
Early in the sixth week, the
  primary palate-median
  palatal process
  (intermaxillary segment)-
  begins to develop.
Initially, this segment,
  formed by merging of the
  medial nasal
  prominences, is a wedge-
  shaped mass of
  mesenchyme between the
  internal surfaces of the
  maxillary prominences of
  the developing maxillae.
                   Primary Palate
The primary palate
  forms the
  anterior/midline
  aspect of the
  maxilla, the
  premaxillary part
  of the maxilla. It
  represents only a
  small part of the
  adult hard palate
  (i.e., anterior to
  the incisive
  fossa).
                     Secondary Palate
The secondary palate is the
   primordium of the hard and soft
   parts of the palate.
The secondary palate begins to
   develop early in the sixth week
   from two mesenchymal
   projections that extend from the
   internal aspects of the maxillary
   prominences.
Initially these structures-the lateral
   palatal processes (shelves)-
   project inferomedially on each
   side of the tongue. As the jaws
   elongate, they pull the tongue
   away from its root, and, as a
   result, it is brought lower in the
   mouth.
                          Secondary Palate
During the seventh and
 eighth weeks, the
 lateral palatal
 processes assume a
 horizontal position
 above the tongue.
 This change in
 orientation occurs by
 a flowing process
 facilitated in part by
 the release of
 hyaluronic acid by the
 mesenchyme of the
 palatal processes.
Bone gradually
  develops in the         Development of
  primary palate,          Hard Palate
  forming the
  premaxillary part of
  the maxilla, which
  lodges the incisor
  teeth
Bone extends from the
  maxillae and palatine
  bones into palatal
  processes to form the
  hard palate. The
  posterior parts of
  these processes do
  not become ossified.
They extend            Soft Palate
  posteriorly
  beyond the nasal
  septum and fuse
  to form the soft
  palate,
  including its soft
  conical
  projection-the
  uvula. The
  median palatine
  raphe indicates
  the line of fusion
  of the palatal
  processes.
A small nasopalatine
  canal persists in the
                           Nasopalatine
  median plane of the         Canal
  palate between the
  anterior part of the
  maxilla and the
  palatal processes of
  the maxillae. This
  canal is represented
  in the adult hard
  palate by the incisive
  fossa, which is the
  common opening for
  the small right and
  left incisive canals
Development of Palate
  Developmental Anomalies of Palate
Clefts of the lip and palate are the
  most common craniofacial
  anomalies. The defects are
  usually classified according to
  developmental criteria, with the
  incisive fossa as a reference
  landmark. These clefts are
  especially conspicuous because
  they result in an abnormal facial
  appearance and defective
  speech. There are two major
  groups of cleft lip and cleft
  palate (Figs. 9-39 to 9-41):
                      Cleft Palate
Unilateral and bilateral
   clefts of the palate
   are classified into
   three groups:
1. Clefts of the
   primary or anterior
   palate
2. Clefts of the
   secondary or
   posterior palate
3. Clefts of the
   primary and
   secondary parts of
   the palate
Clefts of the Primary or Anterior Palate
Clefts of the primary
  or anterior palate
  (i.e., clefts anterior
  to the incisive
  fossa) result from
  failure of
  mesenchymal
  masses in the lateral
  palatal processes to
  meet and fuse with
  the mesenchyme in
  the primary palate.
  Clefts of the Secondary or Posterior Palate
Clefts of the secondary
  or posterior palate
  (i.e., clefts posterior
  to the incisive fossa)
  result from failure of
  mesenchymal masses
  in the lateral palatal
  processes to meet and
  fuse with each other
  and the nasal septum.
   Clefts of the Primary and Secondary
             parts of the Palate
Clefts of the primary and
  secondary parts of the
  palate (i.e., clefts of the
  anterior and posterior
  palates) result from
  failure of the
  mesenchymal masses in
  the lateral palatal
  processes to meet and
  fuse with mesenchyme
  in the primary palate,
  with each other, and the
  nasal septum.
            Etiology of Cleft Palate
Most clefts of the lip and
  palate result from
  multiple factors
  (multifactorial
  inheritance.
Genetic and nongenetic,
  each causing a minor
  developmental
  disturbance.
How teratogenic factors
  induce cleft lip and
  palate is still unclear.