Head And Neck Development II

Question 1

Arch 1 cartilage forms what 2 things?

Answer 1

Jaw joint and part of the wall of the posterior brain case

Question 2

1. Original lateral wall of the skull opens into __
2. What represents the original skull surface?
3. New lateral wall formed to enclose braincase includes? What cartilage is this from?

Answer 2

1. Temporal fossa
2. Zygomatic arch
3. Alisphenoid; arch 1 cartilage

Question 3

Chondrocranium: Name the cartilage precursors for the following

1. Body of occipital (basioccipital)
2. Body of sphenoid (basisphenoid)
3. Ethmoid and components of sphenoid
4. Exooccipital (bones on each side of foramen magnum)

Answer 3

1. Parachordal cartilage
2. Hypophyseal cartilage
3. Prechordal cartilage
4. Occipital somites

Question 4

Sensory capsules are cartilaginous precursors for what 3 things?

Answer 4

Olfactory (nasal cavity), optic (eye), and otic (inner ear, mastoid)

Question 5

Cartilage is formed by what 2 things?

Answer 5

Neural crest and paraxial mesoderm

Question 6

1. Neural crest forms what 2 cartilages and what 2 capsules

2. Paraxial mesoderm forms what 3 things?

Answer 6

1. Hypophyseal cartilage, prechordal cartilage, optic capsule, and olfactory capsule
2. Parachordal cartilage, occipital somites, and otic capsule

Question 7

1. Of the things developed from the neural crest and paraxial mesoderm (previous slide), which 5 are developed by SHH signaling?
2. SHH signaling is from developing __ or __

Answer 7

1. Hypophyseal cartilage, prechordal cartilage, optic capsule, parachordal cartilage, and occipital somites
2. Brain or notochord

Question 8

1. Which 2 are developed from FGF signaling?

2. FGF signaling is from?

Answer 8

1. Olfactory capsule and otic capsule

2. Sensory epithelia

Question 9

Membrane bones:

1. Formed through?
2. Consist of bones of __ face and __
3. Formed from what 2 things?

Answer 9

1. Intramembranous ossification
2. Neurocranium face and mandible
3. Neural crest and mesoderm

Question 10

1. Posterior and anterolateral fontanelles ossify when?

2. Anterior and posterolateral fontanelles ossify when?

Answer 10

1. ~3 months after birth

2. During second year

Question 11

What is cranial stenosis/cranial vault abnormalities caused from?

Answer 11

Premature fusion of fontanelles and cranial sutures

Question 12

3 ways to modify shape of head?

Answer 12

Cradleboards, binding, modern cosmetic devices

Question 13

1. Name 2 groups of muscles that are non-branchial
2. What cranial nerves do they come from?
3. Where are they derived from

Answer 13

1. Occulomotor muscles and tongue muscles
2. Occulomotor= CN III, IV, and VI
   Tongue= CN XII
3. Occulomotor= 1st-3rd somitomere (VI from 6th)
   Tongue= 3rd-4th occipital somites