Development of Orofacial structures Flashcards
What does the viscerocranium become?
Facial skeleton
What bones form from the cartilagenous neurocranium?
- Occipital B.
- Body of sphenoid
- Ethmoid B.
Temporal B.
What bones arise from the membranous neurocranium?
Frontal and parietal Bs.
What bone initially begins as part of the viscerocranium and then migrates to become part of neurocranium?
Frontal B.
Male newborn pt presents with a long, narrow, wedge-shaped head. What is the most likely diagnosis? This most likely results from premature closure of what suture?
Scaphocephaly
Sagittal suture
Male infant that has a high, tower-like head may have what disorder? From premature closure of what suture?
Brachycephaly
Coronal suture
An infant presenting with a twisted, asymmetric head may have what disorder? Due to premature closure of what suture?
Plagiocephaly
Coronal suture
A premature closure of the frontal (metopic) suture may result in what disorder? What bones does this affect?
Trigonocephaly
Frontal and orbital Bs.
What separates the facial primordia from the primordial pharynx? In what week does this rupture?
In what weeks does facial development occur?
Weeks 4-8
At the end of the 4th week, what forms on the inferolateral parts of the frontal nasal prominence?
Nasal placodes
What is the direct embryonic origin of the deep portion of the philtrum of the upper lip?
Intermaxillary segment of MNPs
What pharyngeal arch do the muscles of facial expression come from?
2nd PA
What pharyngeal arch do the muscles of mastication arise from?
PA1
What is the critical period for palatogenesis?
Weeks 6-9 (finishes development at 12)
What is the embryonic origin of the superficial portion of the philtrum of the upper lip?
Maxillary prominence
What part of the palate does the intermaxillary segment give rise to?
Primary palate
What is the embryonic origin of the secondary palate?
Lateral palatine processes (shelves) from the maxillary prominences
What embryonic structures failed to fuse in cleft lip?
Maxillary prominences and median nasal prominences
What structures failed to fuse in a cleft palate?
Lateral palatine process w/ nasal septum and/or medial palatine process
When is the period of development of the nasal septum?
Weeks 9-12
Merged lateral lingual swellings form what part of the tongue?
Anterior 2/3
What pharyngeal arch does the anterior tongue arise from?
PA1
What are the contributions of PAs 2,3, and 4 to form the posterior 1/3 of the tongue?
PA2 (ventromedial) - Copula
PA 3/4 (ventromedial) - hypopharyngeal eminence
Hypopharyngeal eminence overgrows copula to form posterior 1/3 of tongue
What embryological structures do tongue muscles arise from?
Myoblasts of occipital myotomes
NOT NCC
What is glossoschissis?
Bifid tongue (abnormal fusion of lateral lingual swellings)
What is ankyloglossia?
Attachment between tongue and floor of oral cavity is too long and anchors tongue down, limiting movement
What is the order of tooth bud formation? In what week?
Anterior mandibular => anterior maxillary => posterior
Week 6
What cells produce dentin?
Odontoblasts from dental papilla cells
What cells produce enamel?
Ameloblasts from inner enamel epithelium
What stage of odontogenesis are inner enamel and outer enamel epithelium formed?
Cap stage
What stage of odontogenesis are dentin and enamel formed?
Bell stage
What forms from fusino of the IEE and OEE?
Epithelial root sheath => dental root/dental sac
What forms the collagen ligament that anchors tooth to bone?
Outer cells of the dental sac
What cells are responsible for degenerating roots of baby teeth to make room for permanent teeth?
Osteoclasts
