Embryology of head and neck

Question 1

The skull is formed from two major subdivisions

Answer 1

Neurocranium: Surrounds the brain
Viscerocranium: Formes the face and surrounds the oral cavity, pharynx and upper respiratory tract.

Question 2

Chondrocranium (Neurocranium division)

Answer 2

Forms the base of the neurocranium and its derivatives. Protects the internal ear and the nose.
It is laid down first in cartilage and ossifies by endochondral ossification.
Consists: Most of the occipital bone( Basal portion), the Temporal portion( Petrous portion), sphenoid bone forms the base of the skull.
- The ethmoid ossify from cartilage of the nasal capsule.

Question 3

Dermatocranium (Neurocranium division)

Answer 3

Forms lateral and top of parts of the skull. Consists of the paired parietal, frontal as well as the interparietal occipital bone.

Question 4

Membranous viscerocranium

Answer 4

Formed from mesenchyme. 
forms 
1-the paired zygomatic bones 
2-maxillae. 
3- Paired lacrimal 
4-Nasal
5-palatine

Question 5

Cartilaginous viscerocranium:

Answer 5

Formed from the 1st two branches of the pharyngeal arch.