Development of Ear, Nose, Mouth and Throat

Development of Nose

4th weekFACE develops from five primordia that appear in the 4th week: the frontonasal prominence, paired maxillary prominences, and paired mandibular prominences. The oropharyngeal membrane breaks down in the 5th week to form opening to the oral cavity.

Scheme: Langmans Medical Embryology, Sadler, 2004 W-6 end of W-6W-7 W-9DEVELOPMENT OF THE NASAL CAVITIES

DEVELOPMENT OF THE NASAL CAVITIES, PALATE AND TONGUEEnd of W-6W-7.5W-6.5W-10Plane of sections C,E,GIntermaxillary segment, primary palateCNasal cavityOral cavityTongueBrainTongue - Mandibular prominenceOlfactory nervesEyeNasal septumMaxillary prominenceLateral palatine processScheme: Moore and Persaud, Before We Are Born, 1993

Sagittal section of the 160 mm human fetusUpper lipVestibulum (arrows)

Lower lip

Mandible(intramembranousossification)Nasal cavity

Dental papilla

Enamel organ

Hard palate (intramembranous os.)

TonguePhotomicrograph: Collection of HIEM

CLEFT LIP, defect of the upper lip (with or without palate), more common in males (1 : 1,000)

Unilateral cleft lip results from failure of the maxillary prominences on the affected side to unite with the merged medial nasal prominences. The clefts vary from small notch to complete divission of the lip of the lip and alveolar part of the maxilla, cheiloschisis unilateralis, cheilognathoschisis unilateralisScheme: Moore and PersaudBefore We Are Born, 1993W-5

W-6(processes, prominences)

Scheme: Moore and Persaud,Before We Are Born,1993 Bilateral cleft lip of the upper lip results from failure of the maxilary prominences to meet and merge with the medial nasal prominences. In complete bilateral cleft of the upper lip and aleveolar part of the maxilla the intermaxillary segment hangs free (cheilognathoschisis bilateralis)Embryological basis of complete unilateral cleft lipW-7W-10

CLEFT LIP AND PALATEUnilateral cleft of the secondary palate Bilateral cleft of the secondary palate(palatoschisis unilateralis) (palatoschisis bilateralis) Complete unilateral (E), bilateral (F) cleft of the lip and alveolar process of maxilla (cheilognathoschisis) and unilateral/bilateral cleft of the primary palateCheilognathoschisis bilateralis et palatoschisis unilateralis Complete bilateral cleft of the lip and aleveolar process with complete bilateral cleft of the primary and secondary palate Cheilognathopalatoschisis bilateralisCleft palate results from failure of the lateral palatine processes to meet and fuse with each other, the nasal septum,and/or with the primary palate

Cleft palate can be with or without cleftlip, occurs 1 : 2,500, more common infemalesMultifactorial inheritance

FACIAL CLEFTS

Median cleft of the lower lip and mandible (failure of the mandibular prominences to merge completely with each other)

Oblique facial clefts (failure of the maxillary prominences to merge with lateral and medial nasal prominences)

Macrostomia (lateral facial clefts)

Microstomia (excessive merging of the maxillary and mandibular prominences

A single nostril (only one nasal placodeis developed)

Bifid nose (failure of the medial nasal prominences to merge completely)

Schemes: Moore and Persaud, Before We Are Born, 1993