Embryology of Face, Palate and Nasal Cavities Flashcards
What muscles originate from the first pharyngeal arch
Muscles of mastication
What else is formed from the first pharyngeal arch
Maxilla
Mandible
ZYgotmatic and Temporal squamous bones
What is formed from arch 2
Muscles of Facial Expression
What are the 5 facial swellings present from week 4
Frontonasal prominence (with nasal places)
2 x maxillary prominence
2 x Mandibular prominence
Describe the appearance of the nasal places
They are thickened yet flattened areas on the frontonasal prominences
What is the name for the gap that develops into the future mouth
Stomodeum
What are the 4 additional nasal swellings that develop in week 5
2 x Medial nasal swellings
2 x lateral nasal swellings
What structures form around the nasolacrimal duct
The lateral nasal swelling and the maxillary prominence
Where does the naslacrimal groove lie
Between the maxillary prominence and the lateral nasal prominence
What is found in the floor of the nasolacrimal groove
A solid epithelial cord that detaches from the ectoderm
The development of the nasolacrimal duct is largely driven by what
The development of bony structures
Name the prominences of the upper lip
2 medial nasal and 2 maxillary
Name the prominences of the lower lip
Mandibular prominences
Name the prominences of the nose
Frontonasal prominence (bridge and nasal septum)
Medial nasal prominence (crest and tip)
Lateral nasal prominence (alae - sides)
What gives rise to the primary palate
Fusion of medial nasal prominences to give the inter maxillary segment
I.e. where the two medial nasal swellings come together and meet in the midline
What does the labial portion of the intermaxilliary segment give rise to
Philtrum of upper lip
What does the upper jaw component of the intermaxilliary segment give rise to
Carries 4 incisors
What does the palatal component of the intermaxilliary segment give rise to
Forms the primary palate
In terms of the secondary palate, what happens at week 6
Palatine shelves grow down from the Maxillary Prominences
In terms of the secondary palate, what happens at week 7
Shelves ascend (grow down) to horizontal position
Fuse together to form Secondary Palate
Fuse with primary palate anteriorly
What does the incisive foramen represent
The point at which the palatal shelves and primary palate come together
What does the incisive foramen provide
A passage for neurovascular strucutres
What does the uvula present
The most posterior part of the palate where the palatine shelves come together and fuse
What sex is more likely to get a cleft lip
Males
What error of fusion are females most likely to have
Isolated cleft palate
In terms of the nasal cavities, what happens at week 6
The nasal pits depend and penetrate into the underlying mesenchyme
The oronasal membrane separates pits from the oral cavity
How do the nasal cavities communicate with the oral cavity
Via the primitive choanae behind the primary palate
How does the definitive choanae come about
It opens at the junction of the nasal cavity with the pharynx due to the formation of the secondary plate
