Development Cleft lip / palate

face and anterior aspects of mouth…

face & anterior aspects of mouth formed 5-8 weeks

• normal development of face & mouth

  • result of fusion of 5 embryonic processes

    • mandibular right and left

    • frontonasal (nasolateral/median)

    • maxillary processes (2)

Fusion of R & L mandibular processes

• 4 & 5 week gestation

• forms mandible & lower lip

• R & L grow toward each other and fuse at midline

• completed - 6 weeks (embryo)

Frontonasal process grows

• 5th week of gestation

• grow downward into 2 separate processes

  • nasomedial

  • lateral nasal

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  • depression between nasomedian and lateral nasal are olfactory pits (become nasal cavities)

  
  

Lateral nasal processes

• fuse with paired maxillary processes forming nasal alae (flared portion of nostril)

• & anterior aspects of the face below the eyes

Fusion of the nasomedian processes & maxillary processes occurs

• primitive tissue from nasomedian processes become:

  • anterior portion of upper lip

  • anterior aspect of alveolar process (upper teeth / central incisors)

  • anterior aspect of hard palate (premaxilla)

• *PRIMARY palate= columella, anterior lip, alveolar ridge —> incisive foramen

Figure b- facial development complete 8th week gestation

• clefting (lip and/or palate) occur when fusion process between nasomedian and maxillary process is interrupted

Secondary palate includes

• bony hard palate

• soft palate

Anterior aspects of face complete at 8 weeks BUT complete separation of the oral and nasal cavities has not been achieved

• Between 8-12 weeks of gestation

  • embryonic processes that give rise to the hard and soft palate fuse, this separates the oral and nasal cavities

Development of Secondary palate: 2 palatal shelves grow downward from the inner aspects of the maxillary processes

• up to the 9th week the tongue projects into nasal cavity

• growth spurt during 8th and 9th week

  • mandible width and length increase, pulling tongue down away from palatal shelves

• *palatine bones & maxilla = hard palate

Fusion of palate (anterior to posterior)

as palate fuses, nasal septum grows downward to meet palatal shelves in the midline, this separates right and left nasal cavities

Muscles of soft palate evolve from palatal shelf

• SP development during 10th week

• fusion of secondary palate complete at 12 weeks

Definitions: columella, nares, alae

• “little column”

  • tissue underneath nasal tip and between the nostrils

  • made of cartilage & mucosa

  • at lower end of nasal septum

• nares: nostrils

• Alae:

  • two curved sides of nostril

  • made up of base and rim

Veau system

• general reference for nature & extent of clefts

• 4 classes of clefts

• I —> cleft of soft palate only

• II —> cleft of the hard and soft palate to the incisive foramen

• III —> complete unilateral cleft of the soft and hard palate and of the lip and alveolar ridge on one side

• IV —> complete bilateral cleft of the soft and hard palate and/or the lip and alveolar ridge on both sides

• *kiernans Y = people circle where the cleft is

Clefts vary in type and severity, Classification:

• unilateral or bilateral cleft of lip

• unilateral cleft of lip and palate

• bilateral cleft of lip and palate

• submucous cleft

• bifid uvula

Cleft of lip

• involves vermillion portion of upper lip (reddish portion) and may extend into nostril

• Incomplete - minor v shaped notch involving vermillion

• complete - cleft continues through the upper lip into floor of nostril

• effects shape of nose, flaring nostril on side of cleft, columella short and misaligned

Unilateral cleft lip

Unilateral cleft of lip and palate

• extends from the external portion of the upper lip through the alveolus, hard and soft palate

• cleft of palate without cleft of lip can occur

Cleft of palate without lip

Unilateral Cleft of the primary palate

Lip & palate unilateral

Bilateral Cleft of lip and palate

• most severe

• lip and alveolus cleft under both nostrils & prolabium (central portion of lip), alveolar process & premaxilla positioned abnormally at the tip of the nasal septum; protruding mass of tissue

• columella usually absent

Submucous cleft

• muscular cleft in the region of the soft palate

• cleft covered by a thin layer of mucosal tissue

• may not be discovered until later in childhood

Indicators:

• bifid uvula may indicate sub-clefting

• bluish coloration in the middle of the soft palate where muscles fail to fuse (zona pellucida)