Clefts

Question 1

When does a cleft lip occur?

Answer 1

when there is failure of parts of the lip and often alveolar ridge to come together early in the life of a fetus

Question 2

When does a cleft palate occur?

Answer 2

when the midline of the roof of the mouth doesn’t fuse normally during fetal development, leaving an opening between oral and nasal cavity

Question 3

What is a complete cleft?

Answer 3

one that follows the embryological fusion lines and extends all the way to the incisive foramen

Question 4

What is an incomplete cleft?

Answer 4

one that doesn’t extend all the way to the incisive foramen

Question 5

Clefts can be split into 2 categories: primary palate and secondary palate. Describe each including structures and when they should fuse.

Answer 5

primary: structures anterior to the incisive foramen
alveolar ridge and lips
fuse around 7 weeks
secondary: structures posterior to the incisive foramen
hard palate (excluding alveolar), velum, uvula
fuse around 9 weeks

Question 6

What does the “striped Y” model identify? 9 segments

Answer 6

Upper arms of the Y: represent the incisive suture lines of primary palate
Base of the Y: represents the median palatine suture line of the secondary palate
center point: incisive foramen