Development of Face Nose by manilachamara

VIEWS: 489 PAGES: 40

									Development of the Face &
      Nasal Cavity

       Dr. MB Samarawickrama
                        MBBS MS

• Facial prominences
  appear at 4th week

• Form by 1st & 2nd
  Pharyngeal arch.
• Maxillary
  prominences appear
  lateral to the

• Mandibular
  prominences seen
  caudal to this
•Frontonasal prominence form ventntral to the
brain vesicles.
• Both sides of the
  prominence ‘Nasal
  Placodes Originate’.
  – Local thickening of the
    surface ectoderm.
• 5th week

• Nasal Placodes invaginate to form Nasal Pits.

• The ridge of tissue surround the nasal pit form
  the nasal prominences.

  – Lateral nasal prominences
  – Medial nasal prominences
• Next 2 weeks

• Maxillary prominences continue to
  increase in size

• Further medial development causes
  compression of the medial nasal
  prominence towards the midline
• Later the cleft
  between the medial
  nasal prominences &
  prominences is lost
  and two fuse together
• Upper lip is formed by
  – Two medial nasal prominences
  – Two maxillary prominences

• The lateral nasal prominences do not
  participate in forming the upper lip.
• The lower lip and jaw
  form from the
  prominences that
  merge across the
•   Initially
•   The maxillary and lateral nasal prominences
    are separated by a deep furrow
    –   Nasolacrimal groove
• Ectoderm in the floor of this groove forms a solid
  epithelial cord.

• It detaches from the over line ectoderm

• This cord canalized to form the nasolacrimal

• Its upper end widens to form the lacrimal sac
• Later the maxillary & lateral nasal
  prominences merge with each other &
  closed the canal
• Maxillary prominences enlarge and fuse with
  mandibular process to form the cheeks and maxillae
                The nose
• Is formed from five facial prominences.
• Bridge
  – by frontal prominence
• Crest & tip
  – by medial nasal prominences
• Alae
  – lateral nasal prominences
      Intermaxillary Segment

• Two medial nasal prominences merge at
  the surface & deeper level.

• The structure formed by the two merged
  prominences is the inter maxillary
It is composed of
• Labial component
  – philtrum of the upper lip

• Upper jaw component
  – carries the four incisor teeth

• Palatal component
  – form the triangular primary palate
• Intermaxillary segment continue with the
  rostral portion of the nasal septum

• Form by frontal prominence
              Nasal Cavities
During the 6th week
• Nasal pits deepen

• Oronasal membrane separate the oral cavity
  from nasal cavity
  – primitive choanae

These choanae lie posterior to the primitive palate
primitive choanae
• Nasal chamber
  further developed with
  the development of
  secondary palate

• The definitive
  choanae lie at the
  junction of the nasal
  cavity and the
• Paranasal air sinuses develop as
  diverticula of the lateral nasal wall
• Extend into the
  – Maxilla
  – Ethmoid
  – Frontal
  – Sphinoid bones
• They reach their maximum during puberty

• Gives definitive shape to the face
            Nasal Septum
• The nasal cavity
  is separated
  initially by the

• This
• Nasal cavity
  resulting thin
  nasal septum
• Initially it has a free lower margin and the
  cavity communicates with oral cavity

• With the development of the palate nasal
  cavity separate from the mouth and free
  edge merge with palate
 Developmental defects of the face
        and nasal cavity
• Facial Clefts

• Cleft Lip results as abnormalities of

• These defects are due to the lack of fusion
  of the maxillary prominence with the
  medial nasal prominence
• Oblique facial clefts

• A cleft running from the medial angle of
  the eye to the mouth

• failure of the maxillary prominence to
  merge with its corresponding lateral nasal

• Nasolacrimal duct expose to the surface
• Median cleft lip

• Rare abnormality incomplete merging of the two
  medial nasal prominences

• Infant with this abnormality will have other
  midline structure defects
   – e.g. Holoprosencephaly
            » fuse lateral ventricles
            » mental retardation
• Multifactorial

• Incidence:- 1/1000 birth

• Common in males (80%)
Battle sign

To top