embryogenesis cleft lip palate.pdf

7/27/2019 embryogenesis cleft lip palate.pdf

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Ocky Pranata

EMBRY

OGENESIS OF CLEFT LIP

AND PALATE



abnormal opening or a fissure in an anatomical

structure that is normally closed.

Cleft

Clefts of the lip and/or palate are

common birth defects

with an incidence

of 1/500 to 1/1000 births worldwide



Orofacial cleft

Cleft lip and/oralveolus

Cleft palate

Combined





• Cleft lip with or without cleft palate occurs

about twice as often in males than in

females and is usually more severe in males

• Cleft palate occurs about twice in females

as in males



• It has been speculated that it could be related todifferences of the lip and the palate in the embryo.

• In the male human embryo, the horizontal

positioning and subsequent closure of thesecondary palate occurs earlier than in the female

embryo.

•

Because the palatal shelves are open longer in thefemale, there is greater period of time during

which there is susceptibility to environment

teratogens







Stage



• begins at around 6 to 7 weeks of gestation

and starts at the incisive foramen.

•

Fusion begins at the incisive foramen and then proceeds in an anterior direction to form the alveolus

through the fusion of the bilateral incisive suture lines.

• Closure the proceeds to form the base of the anterior

nose and finally the upper lip.• The median and two lateral lip segments are then

fused, forming the philtrum and philtral lines which

completes the formation of the upper lip.

EMBRYOLOGICAL DEVELOPMENT

OF THE LIP AND ALVEOLUS



• During 4th week of gestation, as the maxillary and mandibular

processes of the first pharyngeal arch are developing and

growing anteriorly, a median bulge covering the brain enlarges

and grows forward.

• This frontonasal prominence, with its two lateral thickened

areas, the nasal placodes, develops just above the stomodeum.

Later, the medial and lateral rims of the nasal placodes grow

around the placode, leaving a depression, the nasal pit.

• Continued anterior growth of these rims through the fifth week

causes a thinning and rupture of the epithelium covering the

floor of the nasal pit.





• At this point, as this bucconasal membrane ruptures, a

communication is established with the roof of the developing

oral cavity. The lateral rims of the nasal placodes the lateral

nasal swellings, which will become the alae of the nose. The

medial rims of the nasal placodes, (the median nasal swellings),

fuse together to form the intermaxillary segment form the

bulbus of the nose

• Continued growth of this intermaxillary segment anterior and

inferior to the nose will give rise to the inferior aspect of the

nasal septum, columella of the nose, philtrum of the upper lip,

labial tubercle, and primary palate (premaxilla).





• teeth and their supporting structures as well as the gingiva will also

develop from the intermaxillary segment

• During this approximately 2-week period, the maxillary swellings have

moved anteriorly, meeting the intermaxillary segment and fusing with

it to seal the nasolacrimal groove, a deep furrow running between the

medial aspect of the eye and the primitive oral cavity on the face. The

epithelium lining this groove separates from the surface ectoderm,

finally forming the nasolacrimal duct (tear duct) opening into the

nasal cavity





• During this period, the mandibular processes have

fused anteriorly, forming the mandible, thereby

reducing the size of the primitive mouth. Also at thistime, mesoderm of the second arch has invaded the

area, forming the muscles of facial expression over

the entire face





• starts at around 8 to 9 week of gestation. The

palatal shelves are vertical and positioned on

each side of the tongue.• Around the 7th or 8th week of gestation, the

tongue begin to gradually drop down the

palatal shelves move slowly from a vertical to

horizontal position and fuse, first with the premaxilla at the incisive foramen and then with

each other.

EMBRYOLOGICAL

DEVELOPMENT OF THE PALATE



• The process of fusion begins and the incisive foramen

and then proceeds between the palatal shelves, moving

in a posterior direction along the median palatine

suture line. This completes the formation of the hard

palate.

• The vomer forming a portion of the nasal septum,

moves downward and fuses with the superior surfaceof the hard palate, thus completing the separation of

the nasal cavity. Once the hard palate is formed, the

velum and finally the uvula are formed. This process is

usually complete by 12 weeks of gestation.

EMBRYOLOGICAL

DEVELOPMENT OF THE PALATE













Direction of growth and resorption of the facial

bones at various sites





• due to disruption or delays in cell migration or palatal

shelf movement

• include chomosomal disorders and genetic disorders.

• Older parental age has also been linked with an increased

risk for both cleft lip and palate.

• In addition cleft can be caused by environmental

teratogens or by mechanical factors in utero.

• Environmental teratogens include cigarette smoke,

phenytoin, thalidomide, valium, virus (including rubella

and even influenza), lack of maternal vitamin b6

CAUSES OF CLEFT





THANK YOU

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embryogenesis cleft lip palate.pdf