Embryology of Face, Palate and Nasal Cavities

Question 1

What muscles originate from the first pharyngeal arch

Answer 1

Muscles of mastication

Question 2

What else is formed from the first pharyngeal arch

Answer 2

Maxilla
Mandible
ZYgotmatic and Temporal squamous bones

Question 3

What is formed from arch 2

Answer 3

Muscles of Facial Expression

Question 4

What are the 5 facial swellings present from week 4

Answer 4

Frontonasal prominence (with nasal places)
2 x maxillary prominence
2 x Mandibular prominence

Question 5

Describe the appearance of the nasal places

Answer 5

They are thickened yet flattened areas on the frontonasal prominences

Question 6

What is the name for the gap that develops into the future mouth

Answer 6

Stomodeum

Question 7

What are the 4 additional nasal swellings that develop in week 5

Answer 7

2 x Medial nasal swellings

2 x lateral nasal swellings

Question 8

What structures form around the nasolacrimal duct

Answer 8

The lateral nasal swelling and the maxillary prominence

Question 9

Where does the naslacrimal groove lie

Answer 9

Between the maxillary prominence and the lateral nasal prominence

Question 10

What is found in the floor of the nasolacrimal groove

Answer 10

A solid epithelial cord that detaches from the ectoderm

Question 11

The development of the nasolacrimal duct is largely driven by what

Answer 11

The development of bony structures

Question 12

Name the prominences of the upper lip

Answer 12

2 medial nasal and 2 maxillary

Question 13

Name the prominences of the lower lip

Answer 13

Mandibular prominences

Question 14

Name the prominences of the nose

Answer 14

Frontonasal prominence (bridge and nasal septum)
Medial nasal prominence (crest and tip)
Lateral nasal prominence (alae - sides)

Question 15

What gives rise to the primary palate

Answer 15

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

Question 16

What does the labial portion of the intermaxilliary segment give rise to

Answer 16

Philtrum of upper lip

Question 17

What does the upper jaw component of the intermaxilliary segment give rise to

Answer 17

Carries 4 incisors

Question 18

What does the palatal component of the intermaxilliary segment give rise to

Answer 18

Forms the primary palate

Question 19

In terms of the secondary palate, what happens at week 6

Answer 19

Palatine shelves grow down from the Maxillary Prominences

Question 20

In terms of the secondary palate, what happens at week 7

Answer 20

Shelves ascend (grow down) to horizontal position
Fuse together to form Secondary Palate
Fuse with primary palate anteriorly

Question 21

What does the incisive foramen represent

Answer 21

The point at which the palatal shelves and primary palate come together

Question 22

What does the incisive foramen provide

Answer 22

A passage for neurovascular strucutres

Question 23

What does the uvula present

Answer 23

The most posterior part of the palate where the palatine shelves come together and fuse

Question 24

What sex is more likely to get a cleft lip

Answer 24

Males

Question 25

What error of fusion are females most likely to have

Answer 25

Isolated cleft palate

Question 26

In terms of the nasal cavities, what happens at week 6

Answer 26

The nasal pits depend and penetrate into the underlying mesenchyme
The oronasal membrane separates pits from the oral cavity

Question 27

How do the nasal cavities communicate with the oral cavity

Answer 27

Via the primitive choanae behind the primary palate

Question 28

How does the definitive choanae come about

Answer 28

It opens at the junction of the nasal cavity with the pharynx due to the formation of the secondary plate