Aspects of facial development (research needed)*

Question 1

What has happened by the 4 weeks stage?

Answer 1

• Pharyngeal arches have developed
• Mouth is a slit between the frontonasal process and the mandibular process.
• The nose and nasal cavities do not exist.

Question 2

Explain the formation of the nasal cavity and primary palate.

Answer 2

The lateral and medial nasal processes surround the nasal placodes.

Placodes invaginate backward and medially to cut off the primary nasal septum.

The primary palate begins the separation of the nasal cavities.

Question 3

Explain the formation of the secondary nasal septum.

Answer 3

2 Medially directed processes develop from the medial aspect of each maxillary process.

Tectoseptal Process

Palatine Process

Question 4

What is the tectoseptal process?

Answer 4

Upper nasal septum meets in the middle then turn down to form secondary nasal septum. This completes the seperation of the nasal cavity into 2.

Question 5

Explain the formation of the secondary palate.

Answer 5

The tongue forms in the floor of the mouth and fills the oro-nasal space. The palatine processes are deflected downwards by the tongue.

Question 6

Explain the palatine processes.

Answer 6

This is the stage where all processes have grown to the point where they make contact and begin to fuse together. Fusion occurs with the primary palate and the nasal septum. It is complete at 12 weeks.

Question 7

What happens if the maxillary and mandibular processes are incomplete?

Answer 7

This results in macrostomia.