Development of the Face, Palate & Nasal Cavity

Donna Forbes, Ph.D.Donna Forbes, Ph.D.

University of MinnesotaUniversity of Minnesota

Medical School DuluthMedical School Duluth

Applied Anatomy: Med 6505Applied Anatomy: Med 6505

Fall, 2007Fall, 2007

Face, Palate & Nasal CavityDevelopmentFace, Palate & Nasal CavityDevelopment

4 - 5 weeks4 - 5 weeks 9 weeks 9 weeksPg. 11 notes

Pg. 12

Facial Prominences

FrontonasalFrontonasal

Maxillary (2)Maxillary (2)

Mandibular (2)Mandibular (2)

First Arch

Pg. 12

~ 4 wks

Facial prominences

Frontonasal prominence

Maxillary prominence

Mandibular prominence

2

1

1

1

1

3

Pg. 12

Placodes

Lens of Eye

Inner Ear

= Localized thickenings of surface ectoderm

Pg. 12

Nasal Placodes

Pg. 12

Placodes

Stomodeum

& Stomodeum

Similar to M&P fig 9-26

[10-26]

Transformation of “Prominences” to “Face”

Intermaxillary segment

Philtrum

Primary palate

Premaxilla

Pg. 12 - 13

C D

Growth Migration Fusion

Week 5 Week 6

Week 7 Week 10

Transformation of “Prominences” to “Face”

~ 4.5 wks ~ 6 wks ~ 7 wks

Pg. 12 - 13

1st

2nd1st

1st

2nd

2nd

1st

1st1st

Eyes and Ears

1st

2nd1st

1st

2nd

2nd

Pg. 13

~ 4.5 wks ~ 6 wks ~ 7 wks

Eyes and Ears, cont.

9 weeks4 - 5 weeks

13 weeks

Pg. 13

Details of Eye and Ear Development in the Nervous System Course

Palate Development

Frontonasal prominence Medial nasal prominence Intermaxillary segment

Critical period of development from week 6 to beginning of week 9.

Pg. 13

of the secondary palate

Palate Development

Intermaxillary segment forms the philtrum of the lip, four incisor teeth & primary palate.

Secondary palate formed from the palatine shelves of the maxillary prominences/processes.

Critical period of development from week 6 to beginning of week 9.

Pg. 13

of the secondary palate

Pg. 13

Palate DevelopmentSecondary palate forms from

medial outgrowths of the maxillary prominences known as the palatine shelves. These shelves elevate, grow & fuse in

the midline. The primary & secondary palates fuse with one another at the incisive foramen to form the definitive palate.

Bone develops in the primary palate & anterior part of

secondary palate to form the hard palate. Posterior

secondary palate has no bone & forms the soft palate + uvula.

Nostrils & Nasal CavitiesPg. 14

~ 4.5 wks ~ 6 wks ~ 7 wks

Nasal placodes Nasal pits Nasal sacs

Nasal Cavities

5 weeks

12 weeks7weeks

6 weeks

Pg. 14

Nasal Septum & PalatePg. 14

The nasal septum fuses with the midline region of the definitive palate.

Changes in shape of face

Paranasal air sinuses

Nasal conchae

Tooth development

Pg. 14

Anterior defectsAnterior defectsInvolve upper lip, alveolar part of maxilla & anterior or Involve upper lip, alveolar part of maxilla & anterior or

primary palateprimary palate

Posterior defectsPosterior defectsInvolve hard and soft palate (secondary palate)Involve hard and soft palate (secondary palate)

Combination anterior & posterior defectsCombination anterior & posterior defects

Congenital AbnormalitiesPg. 15

Cleft Lip & Palate

NormalUnilateral cleft lip

& noseUnilateral cleft lip,

jaw, 1° palate

Bilateral cleft lip,jaw, 1° palate

Cleft 2° palate Cleft 2° palate + unilateral cleft lip, jaw, 1° palate

Anterior defect: BPosterior defect: ECombination defects: C, D, F

Pg. 15

Anterior defectsAnterior defectsDue to failure of fusion of Due to failure of fusion of maxillary prominences with the maxillary prominences with the fused medial nasal fused medial nasal prominences.prominences.

Congenital Abnormalities of Lip and Palate Pg. 15

Posterior defectsPosterior defectsDue to failure of fusion of the Due to failure of fusion of the palatine shelves with one palatine shelves with one another, with the nasal septum another, with the nasal septum & with the posterior margin of & with the posterior margin of the primary palate.the primary palate.

Know this!

Teratogens interfere with Teratogens interfere with migration of neural crestmigration of neural crest so that there so that there is too little mesenchyme to work with. Examples include:is too little mesenchyme to work with. Examples include:

Anticonvulsants such as DilantinAnticonvulsants such as Dilantin Vitamin A; isotretinoin (Accutane)Vitamin A; isotretinoin (Accutane)

GeneticGenetic Chromosomal syndromes (e.g. Trisomy 13)Chromosomal syndromes (e.g. Trisomy 13) Single gene mutationsSingle gene mutations

Other:Other: Excessive cell death during the formation of the maxillary & Excessive cell death during the formation of the maxillary &

nasal prominencesnasal prominences Failure of palatal shelves to elevate at the proper timeFailure of palatal shelves to elevate at the proper time Excessively wide headExcessively wide head

Congenital Abnormalities: Etiology is Multifactorial Pg. 15

Cleft Lip & PalatePg. 15

Incomplete unilateral cleft lip

Bilateral cleft lip involving lip, jaw &

1° palate

Unilateral cleft lip cleft jaw, 1° palate +

cleft of 2° palate

Movies

Face Development

Front view 3/4 view Side view

Click on an image or its title & wait for the movie to load. They are slow to appear.

Movies

Face Development

Click on the words “Face Development”

& wait for the movie to load.

“Cases to Consider”

Discussion of these cases will be sent out as an email after you have some time to

consider them.

Pg. 16

Now for the “T-Quiz”!

Thymus

Thyroid

Tongue

Tonsil

Trachea

Trigeminal nerve

Tympanic cavity

Tympanic membrane

Origin:

Answers to this

“T-Quiz” are on the last slide.

Questions?

Answers to the “T’s”!

Thymus 3rd Pharyngeal Pouch

Thyroid Floor of pharynx between arches 1 & 2 + parafollicular cells from the 4th pouch

Tongue Floor of pharynx including arches 1 thru 4

Tonsil 2nd Pharyngeal Pouch + Mesenchyme

Trachea Laryngotracheal diverticulum

Trigeminal nerve Trigeminal Ganglion & Brain Stem

Tympanic cavity 1st Pharyngeal Pouch

Tympanic membrane Ectoderm of external auditory meatus, Mesoderm, Endoderm of tympanic cavity

Origin: