Development of Orofacial Structures

Question 1

which bones in the neurocranium form by endochondral ossification?

Answer 1

occipital bone–> body of sphenoid bone—> ethmoid bone, and the petrous and mastoid parts of the temporal bone

Question 2

which bones in the neurocranium form by intramembranous ossification?

Answer 2

frontal bone and the parietal bones

Question 3

which bones in the viscerocranium form by endochondral ossification?

Answer 3

malleus and incus (PA1), stapes, styloid process of temporal bone, and lesser horn of hyoid bone (PA2), greater horns of hyoid bone (PA3), laryngeal cartilages (PA4)

Question 4

which bones of the viscercranium form by intramembranous ossification?

Answer 4

squamous temporal bones, maxillary, zygomatic bones, and the mandible

Question 5

what is the term for premature fusion of the sutures?

Answer 5

craniosynostosis

Question 6

which suture is prematurely closed in scaphocephaly?

Answer 6

sagittal suture

Question 7

how does the cranium look with cases of scaphocephaly?

Answer 7

long, narrow, and wedge shaped

Question 8

which suture is prematurely closed in brachycephaly?

Answer 8

coronal suture

Question 9

how does the cranium look in cases of brachycephaly?

Answer 9

high, tower-like, dome-shaped

Question 10

which suture is prematurely closed in plagiocephaly?

Answer 10

coronal or lambdoidal suture on ONE SIDE

Question 11

how does the cranium look in cases of plagiocephaly?

Answer 11

twisted and asymmetric

Question 12

which suture is prematurely closed in trigonocephaly?

Answer 12

frontal (metopic) suture

Question 13

how does the cranium look in cases of trigonocephaly?

Answer 13

malformation of the frontal and orbital bones

Question 14

what are the facial primordia?

Answer 14

1 frontonasal prominence, 2 maxillary prominences, and 2 mandibular prominences

Question 15

what is the term for the primitive mouth?

Answer 15

stomodeum

Question 16

when does the oropharyngeal membrane rupture?

Answer 16

day 26

Question 17

what happens when the oropharyngeal membrane ruptures?

Answer 17

facial development begins

Question 18

what is the first part of the face to form?

Answer 18

lower jaw/lower lip

Question 19

when do nasal placodes form on the inferolateral parts of the FNP?

Answer 19

end of the 4th week

Question 20

what happens when the nasal placode edges proliferate?

Answer 20

it produces a medial and lateral nasal prominence

Question 21

what do the nasal pits eventually form?

Answer 21

nostrils and nasal cavities

Question 22

what do the lateral nasal prominences form?

Answer 22

alae (sides) and the nose

Question 23

what structure in the pharyngeal apparatus forms the external auditory meatus?

Answer 23

1st groove

Question 24

how does the medial nasal prominence move toward the midline?

Answer 24

with the maxillary prominences growing toward midline

Question 25

when the maxillary prominences make contact with the lateral nasal prominences, what does it form?

Answer 25

nasolacrimal groove

Question 26

when will the nasolacrimal groove begin to fill in?

Answer 26

by the end of the 6th week

Question 27

what is the lateral nasal prominence and the maxillary prominence separated by?

Answer 27

the nasolacrimal groove

Question 28

When does facial development occur?

Answer 28

between the 4th and 8th weeks

Question 29

Which pharyngeal arch does the maxillary prominence and mandibular prominence come from?

Answer 29

PA 1

Question 30

Where do the MNP and LNP leave and go sit?

Answer 30

nasal pit

Question 31

what are nasal placodes derived from?

Answer 31

surface ectoderm

Question 32

when do medial nasal prominences merge with maxillary and lateral nasal prominences?

Answer 32

between the 7th-10th weeks

Question 33

as the medial nasal prominences merge, what forms?

Answer 33

the intermaxillary segment

Question 34

what is considered the premaxillary part of the maxilla?

Answer 34

the intermaxillary segment

Question 35

what is considered the core of the philtrum of the upper lip derived from?

Answer 35

the intermaxillary segment

Question 36

the surface of the upper lip is derived from what?

Answer 36

the maxillary prominence

Question 37

most of the upper lip, maxilla, and secondary palate forms from what?

Answer 37

maxillary prominences

Question 38

what are the primordial nasal sacs separated from the oral cavity by?

Answer 38

oronasal membrane

Question 39

when does the oralnasal membrane rupture?

Answer 39

end of the 6th week

Question 40

when does palatogenesis begin?

Answer 40

6th week of development

Question 41

when does palatogenesis end?

Answer 41

by 12th week

Question 42

what is considered the critical period of palatogenesis?

Answer 42

end of 6th week--> beginning of 9th week

Question 43

what is another name for the intermaxillary segment?

Answer 43

the median palatine process

Question 44

when does development of the secondary palate occur?

Answer 44

early in the 6th week

Question 45

what does the secondary palate develop from?

Answer 45

the lateral palatine processes aka the palatine shelves

Question 46

what does the lateral palatine processes/ palatine shelves arise from?

Answer 46

mesenchyme of the maxillary prominences

Question 47

what is the first step in development of the secondary palate?

Answer 47

the palatine processes will extend inferiorly on each side of the tongue

Question 48

what happens in the face that moves the tongue out of the way when the secondary palate is growing?

Answer 48

the mandible elongates, which pulls the tongue forward and down

Question 49

what is the final step of the formation of the secondary palate?

Answer 49

the palatine processes will "flip" horizontally to be above the tongue

Question 50

when is secondary palate formation complete?

Answer 50

7-8th weeks of development

Question 51

how is the hard palate formed?

Answer 51

when bone extends from the maxillae and palatine bones into the lateral palatine processes

Question 52

what indicates the line of fusion in the palate?

Answer 52

the palatine raphe

Question 53

in cases of cleft lip, what is there a lack of fusion of?

Answer 53

lack of fusion between the maxillary prominences and median nasal prominences

Question 54

in cases of cleft palate, what is there a lack of fusion between?

Answer 54

lack of fusion between either the lateral palatine processes with the nasal septum or the lateral palatine process with the median palatine process

Question 55

what is the nasal septum?

Answer 55

down growth from internal parts of merged medial nasal prominences

Question 56

when does fusion of nasal septum and the palatine process begin?

Answer 56

9th week

Question 57

when is fusion of the nasal septum and the palatine process completed?

Answer 57

by the 12th week

Question 58

what is the first indication of tongue development?

Answer 58

the median lingual swelling

Question 59

where is the median lingual swelling located?

Answer 59

in the floor of the primordial pharynx

Question 60

when does the median lingual swelling appear?

Answer 60

at the end of the 4th week

Question 61

what is located on each side of the median lingual swelling?

Answer 61

lateral lingual swellings

Question 62

all tongue buds result from what?

Answer 62

proliferation of mesenchyme in the ventromedial parts of PA1

Question 63

what happens to the lateral lingual swellings?

Answer 63

they rapidly proliferate, merge, and overgrow the median lingual swelling

Question 64

what do the merged lateral lingual swellings form?

Answer 64

the oral part, anterior 2/3 of the tongue

Question 65

when the ventromedial parts of PA2 fuse, what do they form?

Answer 65

the copula

Question 66

what do the ventromedial parts of PA3 and PA4 develop?

Answer 66

the hypopharyngeal eminence

Question 67

what happens to the hypopharyngeal eminence?

Answer 67

it overgrows the copula, forming the posterior 1/3 of the tongue

Question 68

tongue musculature is derived from what?

Answer 68

myoblasts of the occipital myotomes

Question 69

what is incomplete fusion of the lateral lingual swelling/ bifed tongue?

Answer 69

glossoschissis

Question 70

what is it called when the frenulum is short and extends to the tip of the tongue?

Answer 70

ankyloglossia