Development of Face Flashcards
What are the five facial prominences that develop around the stomodeum?
Frontonasal prominence (1), maxillary prominences (2), mandibular prominences (2).
What is the stomodeum?
A shallow depression in the face that forms by longitudinal folding of the early embryo.
By when does the embryo have a distinct human appearance?
By the end of the second month.
What structure forms the middle part of the stomodeum?
The frontonasal prominence.
What prominence is lateral to the stomodeum and part of the first pharyngeal arch?
The maxillary prominence.
What prominence is caudal to the stomodeum?
The mandibular prominence.
What are nasal placodes and when do they appear?
Thickened ectodermal structures that appear in the 4th week and give rise to the nose and nasal cavities.
What forms the bridge of the nose?
The frontonasal process.
What forms the dorsum and tip of the nose?
Two fused medial nasal processes.
What forms the sides and alae of the nose?
Two lateral nasal processes.
What structure gives rise to the philtrum of the upper lip?
The nasomedial processes.
What separates the nasal sacs from the oral cavity during early development?
The oronasal membrane.
What are the primitive choanae?
The openings that form after the oronasal membrane ruptures, connecting the nasal and oral cavities.
What is the primary palate derived from?
The medial frontonasal processes.
What does the secondary palate develop from?
The maxillary processes.
What forms the nasal septum?
A downgrowth of the frontonasal process.
What forms the lower lip and lower part of the cheek?
The two mandibular processes.
What structure gives rise to the oral fissure?
The opening of the stomodeum.
What is a cleft lip?
Failure of fusion of the embryonic facial prominences affecting the lip.
What is a cleft palate?
Failure of fusion of the palatal shelves, resulting in a connection between the nasal and oral cavities.
What is a median cleft lip?
Failure of the medial nasal prominences to merge and form the intermaxillary segment.
What is an oblique facial cleft?
Failure of the maxillary prominence to fuse with the lateral nasal prominence.
