Head and neck embryology

Question 1

What is mesenchyme?

Answer 1

embryonic connective tissue

Question 2

What does the neck develop from?

Answer 2

branchial/pharyngeal arches

Question 3

What does the face develop from?

Answer 3

5 mesenchymal processes/prominences

Question 4

What does the skull develop from?

Answer 4

mesenchyme in the head

Question 5

How many branchial arches are there?

Answer 5

5

1,2,3,4,6

Question 6

What are the branchial arches?

Answer 6

Series of arches which develop around the future mouth and pharynx to offer support to the primitive pharynx

Question 7

What week does the branchial arches form?

Answer 7

late week 4 - week 6

Question 8

What forms the clefts and what forms the pouches inbetween arches?

Answer 8

clefts - ectoderm

pouches - endoderm

Question 9

What does the mesoderm form in the branchial arches?

Answer 9

cartilage, muscles

Question 10

Nerves of branchial arches number sequence to remember

Answer 10

5,7,9,10,10

Question 11

1st arch nerve supply

Answer 11

mandibular branch of trigeminal nerve

Question 12

2nd arch nerve supply

Answer 12

facial nerve

Question 13

3rd arch nerve supply

Answer 13

glossopharyngeal nerve

Question 14

4th arch nerve supply

Answer 14

superior laryngeal branch of vagus

Question 15

6th arch nerve supply

Answer 15

recurrent laryngeal branch of vagus

Question 16

What branch have all the muscles of facial expression derived?

Answer 16

2nd

Question 17

Digastric - anterior and posterior belly nerve supply and arch derivation

Answer 17

anterior - V3
posterior - facial nerve
arch 1 and 2

Question 18

What group of muscles must arise from branchial arch 1?

Answer 18

muscles of mastication

Question 19

What skeletal elements form from the branchial arches?

Answer 19

hyoid bone, incus, malleus, mandible etc

Question 20

Other important structures developing from branchial arches

Answer 20

thyroid and parathyroid glands, part of pituitary gland and tongue

Question 21

Name the 5 processes/prominences which form the face

Answer 21

1 frontonasal
2 maxillary
2 mandibular

Question 22

What clinical importance is it to know the 5 processes of facial development?

Answer 22

congenital defects = clefts

Question 23

Placode

Answer 23

thickening

Question 24

What makes the primary and secondary palate?

Answer 24

median nasal processes forming philtrum

palatine shelves from maxillary process meet

Question 25

What is the importance of the palate?

Answer 25

separate nasal and oral cavity

Question 26

What is the cranial vault and how is it formed?

Answer 26

flat bones of skull joined by sutures
membranous ossification
not joined at birth

Question 27

Craniosynotosis…

Answer 27

sutures joined much earlier than they should be

Question 28

Base of skull formation

Answer 28

endochondral - preformed in cartilage and then later ossified as irregular bones

Question 29

What is the viscerocranium formed from?

Answer 29

brachial arches and sensory capsules

Question 30

What are sensory capsules and how are they formed?

Answer 30

form bones around sense organs

preform in cartilage