Facial growth and development Flashcards
Role of neural crest cells?
arise from cranial region of neural tube -ectomesenchyme tissue which migrates between the ectoderm and mesioderm and can differentiate into different cell types
role of pharyngeal arches?
6 pairs of arches decreasing in size form cranial to caudal.
Derived form migrating neural crest cells.
Separated by grooves externally and pouches internally
Each arch consists of cartilage rod, muscular, vascular and nerve component
Fist and second are important in craniofacial development
what occurs at 6 week?
Nasal placode appear to send down to form nasal pits as the mesoderm tissue proliferates around them
At the sam time the maxillary processes of the first arch begin to grow inwards
By the end maxillary processes fuse with the medial nasal processes to form the upper lip
what is formed at week 8?
Primitive choana
cleft lip?
Occurs when the medial nasal prominence and maxillary prominence fail to fuse
cleft palate?
Can occur in isolation when the palatal shelves fail to fuse in the midline, or in combination with cleft lip
palatal development?
The fronto-nasal process grows down to form the primary palate (extends to the incisive papilla)
Maxillary processes then develop shelf like process the palatine shelves that grow vertically downwards either side of the tongue
what is the critical period for face and palate development?
6-12 weeks IU
Image 1 vs 2?
Isolated incomplete cleft of are and soft palate (lip and alveolus intact)
Complete cleft of palate (with lip and alveolus involvement)
- speech problems
Intramembranous ossification?
Membrane bone activity no cartilage replacement
- calvarium, facial bones, mandible and clavicle
endochondral ossification?
Bony replacement of cartilage
- most bones in the body grow
Limb bones, axial skeleton (vertebra) and cranial base
synchondosis?
Growth plates (primary growth cartilages) between cranial base plates that are important in antero-posterior growth of the skull with endochondral ossification
name the 3 synchondrosis in the cranial base?
Sphenoid-ethmoidal, inter Sphenoidal and spheno-occipital (most important facial graph)
2 most important growth patterns with regards to craniofacial growth?
Neural and somatic
neural growth pattern?
Determined by growth of the brain
Rapid and compete by 7-8 years of age, calvarium follows this pattern so head size little change beyond this age
somatic growth pattern?
General growth pattern of most strictures including maxilla and mandible (same pattern as body length/height)
Starts rapidly and slows in pre-pubertal periods with acceleration again at puberty
craniosynostosis?
Premature fusion of th suture of the alvarium before birth
Can lead to increased ICP
Head deformity - type depends on which suture/sutures are fused
Restricts rain growth and development
what syndrome can craniosynostosis be apart of
Aperts syndrome (genetic)
Aperts syndrome?
Premature fusion of coronal sutures so wide head side/side but shower form and back
Wide shallow eye sockets (bulging eyes-proptosis), growth of maxilla and zygomatic also affected
Ten associated with cleft palate and webbed fingers
cranail base develops by what pattern?
Endochondral
