Chapter 4: Face and Neck Development

Question 1

What are the FIVE major facial processes/prominences (growth centers) that form during the fourth week? What does each process give rise to?

Answer 1

Single frontonasal process - Upper face
Paired maxillary processes - Midface
Paired mandibular processes- Lower face

Question 2

What is the globular process?

Answer 2

Single process that is formed when the medial nasal processes join together

Question 3

What does the medial nasal process give rise to?

Answer 3

Middle of nose and septum
Upper lip and philtrum
Anterior of alveolus - 4 maxillary incisors
Primary palate

Question 4

What is the primary palate also known as? (2)

Answer 4

Premaxilla
Intermaxillary segment

Question 5

What does the lateral nasal process give rise to?

Answer 5

Lateral walls of right and left nasal cavities

Question 6

How is the Maxillary process formed?

Answer 6

Outgrowth of first pharyngeal (branchial) arch

Question 7

What does the maxillary process form?

Answer 7

Upper cheeks, upper lip (except philtrum). maxilla, secondary palate

Question 8

What does the mandibular process form?

Answer 8

Lower face, lower cheeks, lower lip, mandible

Question 9

From what branch is the mandibular process formed

Answer 9

from the 1st pharyngeal arch

Question 10

How is the mandibular process formed?

Answer 10

Meckel’s cartilage joins the 2 mandibular processes at the midline (later replaced by bone)

Question 11

What is the mandibular symphysis

Answer 11

midline seam where the mandibular bone joins

Question 12

What happens at the beginning of week 4?

Answer 12

The primitive mouth becomes the stomodeum

Question 13

When does the oropharyngeal membrane disintegrate?

Answer 13

End of week 4

Question 14

How does Meckel’s cartilage disappear?

Answer 14

Through intramembranous ossification when the bony mandible forms

Question 15

What are placodes

Answer 15

Rounded areas of specialized, thickened ectoderm found in locations of developing special sense organs

Question 16

What are the three sets of placodes that form in the facial area

Answer 16

Lens palcodes
Otic placodes
Nasal placodes

Question 17

What happens to the nasal placodes

Answer 17

become submerged and form a depression to become the nasal pits

Question 18

What is the oronasal membrane

Answer 18

separates the stomodeum from the nasal sacs

Question 19

Briefly explain how the median nasal processes develop

Answer 19

Appear as two crescent-shaped swellings between nasal pits

Question 20

Briefly explain the lateral nasal processes

Answer 20

Develop from outer crescent-shaped swellings

Question 21

When does the intermaxillary segment/premaxillary segment develop?

Answer 21

Starts at week 5 and continues to week 7

Question 22

Describe the maxillary process

Answer 22

Adjacent swellings from increased growth of mandibular arch on each side of stomodeum

Question 23

What forms during the 6th week?

Answer 23

Upper lips

Question 24

How does the upper lip form

Answer 24

When each maxillary process fuses with each medial nasal processes on both sides of stomodeum

Question 25

What contributes to the upper lip

Answer 25

Maxillary processes

Question 26

What contributes to the philtrum

Answer 26

Two medial nasal processes

Question 27

How does cleft lip occur

Answer 27

Failure of fusion of maxillary process with medial nasal process

Question 28

What feature develops parallel to the face from week 4 to fetal period?

Answer 28

Neck development

Question 29

Branchial grooves are

Answer 29

Outer side of branchial arch; branchial clefts;pharyngeal grooves

Question 30

Pharyngeal pouches

Answer 30

inner walls/endodermal evaginations

Question 31

1st branchial arch

Answer 31

Mandibular arch processes; gives rise to maxillary arch
Meckel’s cartilage

Question 32

2nd branchial arch

Answer 32

Hyoid arch
Reichert cartilage

Question 33

3rd Branchial arch

Answer 33

formation of parts of hyoid bone and tongue