Gakunga 1 Flashcards
Facial primordia appear early in the ____ week, and coincides with
mouth opening.
fourth week
Facial prominences (frontonasal, maxillary, mandibular) are produced by proliferation of cranial _______.
neural crest cells
Facial development occurs mainly between the ______ weeks
fourth and eighth
______ (developed from nasal placodes) move toward the midline, where your nose will be
nasal pits
The _______ forms at the boundary between pharyngeal arches 1 and 2.
external ear
Fusion vs Merging
In fusion, there is a breakdown. Merging is a reconfiguration.
Name the five processes that fuse during development
2 maxillary, 2 mandibular, frontonasal
Stomodeum
Primitive mouth (the five process fuse around this)
An elevation on the face anterior to the brain bulge
Frontal Prominence
- Thickening of ectoderm on the frontal prominence
- Indicates the development of the future nose
Nasal Placode
- Depression in the nasal placode indicating the external nares
- Note the openings of the nasal cavity are separate from each other
Nasal Pit
Horseshoe shaped ridge along the superior aspect of the nasal pits
Nasal Processes
- Medial portion of the horseshoe shaped ridge
- Contributes to portions of the upper lip
Medial Nasal Process
- Lateral portion of the horseshoe shaped ridge
- Contributes to the lateral portion of the nose
Lateral Nasal Process
______ sink into nasal pits, the precursors of nostrils and nasal cavities
Nasal placodes
_______ form sides of nose
Lateral nasal prominences
______ fuse, form nasal septum and ethmoid bone.
Medial nasal prominences
Medial nasal prominences
merge with each other and with ________.
maxillary prominences
_______ separate the lateral nasal prominences from the maxillary prominences
Nasolacrimal grooves
By the end of the fifth week, six auricular hillocks indicate development of the _____.
external ear
The ______ are initially located in the neck region, but ascend to sides of head, at level of eyes
external ears
Fusion of the Medial Nasal Processes forms which external features of the face?
- Bridge of the nose
- Philtrum of the lip
Fusion of the Medial Nasal Processes forms which internal structures?
- Incisor bearing segment of the maxilla
- Primary palate
- Lateral outgrowth of the mandibular arch
- Contributes to the formation of the maxilla
Maxillary Process
Portion of the first arch which forms the mandible
Mandibular Process
Fusion of the Medial Nasal Processes and the Maxillary Processes forms which external feature?
Upper lip
Fusion of the Medial Nasal Processes and the Maxillary Processes forms which internal feature?
Maxillary arch
External Structures from the Maxillary Process
- Infraorbital region
- Cheek
External Structure from the Lateral Nasal Process
Ala of the nose
Fusion of the Mandibular Processes results in which external feature?
- Lower lip
- Chin
Fusion of the Mandibular Processes results in which internal feature?
Mandibular arch
Mandible develops in close relation to nerve of the first arch, _____.
Trigeminal nerve (V)
Mandibular branch of trigeminal nerve –> ______ (medial to Meckel’s
cartilage) + ______ (lateral to Meckel’s cartilage)
- lingual nerve
- inferior alveolar nerve
___ weeks: mesenchyme condensation on lateral aspect of Meckel’s cartilage
6
___ weeks: intramembranous ossification center –> first bone of the mandible
7
Mandibular canal forms around _______.
inferior alveolar nerve
Medial and lateral _____ develop in relation to tooth germs
alveolar plates
Ossification spreads posteriorly into
remaining mesenchyme of first arch, to form the ____ of the mandible
ramus
The _____ marks the site at which the continued ossification diverged from
Meckel’s cartilage
lingula
By ____ weeks, the rudimentary mandible has formed, almost exclusively through intramembranous
bone formation
10
Fate of Meckel’s cartilage
- Malleus
- Sphenomalleolar ligament
- Sphenomandibular ligament
- Tiny contribution to mandible
Articulation between the temporal bone and mandible
temporomandibular joint (TMJ)
Two lateral swellings of the mandibular arch
Lateral Lingual Swellings
A single mid-line swelling from the mandibular arch
Tuberculum Impar
- A single mid-line swelling posterior to the tuberculum impar
- Derived from 2nd, 3rd and 4th arches
Copula
- Mostly from the forward growth of the lateral lingual swellings fusing with the tuberculum impar
- There may be some contribution to the mucosa from the second arch because of its innervation from the facial nerve
Body or Anterior 2/3 of the Tongue
Develops from the copula
Root or Posterior 1/3 of the Tongue
- Small triangular anterior portion of the hard palate
- Forms from the fusion of two medial nasal processes
Primary palate
Medial nasal prominences fuse with each other, and with the maxillary
prominences, to form the
_____; philtrum of lip and median palatal process form from _______.
- upper lip
- MNPs (intermaxillary segment)
- Forms by the fusion of the palatine shelves which are outgrowths of the maxillary process
- Initially vertical in position with tongue in between
Secondary Palate
Types of Cleft Lip and Palate
- Clefts of anterior
(primary) palate-anterior to
incisive foramen; usually
involve upper lip and alveolar
process of maxilla - Clefts of anterior and
posterior palate - Clefts of posterior
(secondary) palate
- Clefts can be unilateral or
bilateral
Cleft repair:
3 months – ______
1.5 years – ______
9 years – _______ to facilitate eruption of permanent canine and lateral incisor (if present)
- Lip closure
- Close palate
- Graft alveolus
