Anatomy lab 2 - Dental Eruption

Question 1

when do lower central incisors erupt

Answer 1

6 months

Question 2

when do upper central incisors erupt

Answer 2

8-12 months

Question 3

when do upper lateral incisors erupt

Answer 3

9-13 months

Question 4

when do lower lateral incisors erupt

Answer 4

10-16 months

Question 5

when do upper first molars erupt

Answer 5

13-19 months

Question 6

when do lower first molars erupt

Answer 6

14-18 months

Question 7

when do upper canines erupt

Answer 7

16-22 months

Question 8

when do lower canines erupt

Answer 8

17-23 months

Question 9

when do lower second molars erupt

Answer 9

23-21 months

Question 10

when do upper second molars erupt

Answer 10

25-33 months

Question 11

order of eruption of deciduous dentition

Answer 11

81, 71
51, 61
52, 62
82, 72
54, 64
84, 74
53, 63
83, 73
85, 75
55, 65

Question 12

5 purposes of primary teeth

Answer 12

Reserve space for permanent successors

Help development of speech

Help aid good nutrition

Missing or decayed teeth makes mastication difficult
- more likely to reject food

Healthy start to permanent teeth
- decay and infection on primary teeth can cause dark spots on adult teeth developing beneath them

Question 13

what age do permanent teeth begin erupting

Answer 13

6 years

Question 14

when do lower first permanent molar erupt

Answer 14

6-7 years

Question 15

when do upper first permanent molars erupt

Answer 15

6-7 years

Question 16

when do permanent lower central incisors erupt

Answer 16

6-7 years

Question 17

when do permanent lower lateral incisors erupt

Answer 17

7-8 years

Question 18

when do permanent upper central incisors erupt

Answer 18

7-8 years

Question 19

when do permanent upper lateral incisors erupt

Answer 19

8-9 years

Question 20

when do permanent lower canines erupt

Answer 20

9-10 years

Question 21

when do permanent upper first premolars erupt

Answer 21

10-11 years

Question 22

when do permanent lower first premolar erupt

Answer 22

10-12 years

Question 23

when do permanent upper second molar erupt

Answer 23

10-12 years

Question 24

when do permanent lower second premolars erupt

Answer 24

11-12 years

Question 25

when do permanent upper canines

Answer 25

11-12 years

Question 26

when do permanent lower second molars erupt

Answer 26

11-13 years

Question 27

order of eruption of permanent teeth

Answer 27

``` 36, 46 16, 26 31, 41 11, 21 12, 21 33, 43 14, 2 34, 44 17, 18 35, 45 13, 23 37, 47 ``` 8s

Question 28

at what age are most permanent teeth erupted by

Answer 28

13 3rd molars between 17 and 21

Question 29

synchondrosis

Answer 29

A primary cartilaginous joint Mainly found in the developing skeleton (e.g. growth plates) - adult example – between the first rib and sternum Hyaline cartilage between the two bone surfaces with very little movement permitted - Bone replacing cartilage, when replaced fully by bone = growth stops

Question 30

locations of secondary cartilaginous joint/symphysis (3)

Answer 30

midline of body inter-vertebral discs pubic symphysis of pelvis

Question 31

spheno-occipital synchondrosis

Answer 31

Between the sphenoid and occipital bones Allows growth of the base of the skull

Question 32

when is the spheno-occipital synchondrosis open until

Answer 32

16-20 years

Question 33

role of spheno-occipital synchondrosis

Answer 33

Persists throughout growth and development ``` Allows growth to occur - Proliferate - Expand Space for permanent molars Maxilla expanding backwards and space for nasopharynx ```

Question 34

ossification centre

Answer 34

Starting point for bone growth Some bones in skull develop from several ossification centres, which later fuse into a single bone First ossification centre to appear is the primary ossification centre

Question 35

endochondral ossification

Answer 35

cartilage laid down first followed by bone

Question 36

intramembranous

Answer 36

bone laid down directly into mesenchyme (early embryonic tissue)

Question 37

long bone is where

Answer 37

arms and legs

Question 38

ossification of long bones

Answer 38

Cartilage precursor Endochondral ossification ``` Cartilage Starts to expand - Can grow through interstitial growth whereas - Can divide - Bone laid down onto something BV enter cartilage when get big enough ``` Cartilage begins to calcify when large enough - Bone can be laid onto - Primary ossification centres Secondary ossification centres at either end - Maintain a cartilaginous plate in between them - ---Synchondrosis - primary cartilaginous joint - ---Allows bone to keep growing, replacing cartilage by bone and until growth stops

Question 39

ossification of skull

Answer 39

both types endochondral - occipital bone - mandible intra membraneous - rapidly growing bones (frontal, partietal) - surrounding the brain

Question 40

which area of the skull forms by endochondral ossification

Answer 40

bottom area (occipital, manidble) rest is intramembraneous

Question 41

how many ossification centres does the occipital bone have

Answer 41

6 centres | - 2 paired and 1 single

Question 42

when do the ossification centres of the occipital bone fuse

Answer 42

``` squamous parts (3/4) fused by birth the rest fuse by 6/7 years ```

Question 43

fontanelles

Answer 43

Tough Membranous areas ‘soft spots’ between bones of calvarium (neurocranium) Allow for compression and overlap of bones during birthing - Head can appear slightly distorted for several days following birth Also important for continued rapid growth of brain after baby is born

Question 44

2 roles of fontanelles

Answer 44

Allow for compression and overlap of bones during birthing - Head can appear slightly distorted for several days following birth Also important for continued rapid growth of brain after baby is born

Question 45

how many fontanelles are there

Answer 45

6 TOTAL 1 anterior 1 posterior 2 mastoid (posterolateral) 2 sphenoidal (anterolateral)

Question 46

order in which fontanelles close postpartum

Answer 46

Between 1-3 months – posterior fontanelle around 6 months – sphenoidal (anterolateral) fontanelle Between 6-18 months - Mastoid (posterolateral) fontanelle by around 2 years – anterior fontanelle

Question 47

when does the posterior fontanelle close

Answer 47

1-3 months post partum

Question 48

when does the sphenoidal fontanelles (anterolateral) close

Answer 48

around 6 months post partum

Question 49

when does the mastoid fontanelles (posterolateral) close

Answer 49

between 6-18 months post partum more variable

Question 50

when does the anterior fontanelle close

Answer 50

around 2 years post partum

Question 51

posterior fontanelle is between

Answer 51

parietal and occipital bones

Question 52

sphenoidal (anterolateral) fontanelle is between

Answer 52

parietal, frontal, sphenoid and temporal bones

Question 53

mastoid (posterolateral) fontanelle is between

Answer 53

occipital, parietal and temporal bones

Question 54

anterior fontanelle is between

Answer 54

parietal and frontal bones

Question 55

apart from fontanelles where are other areas of growth in the skull

Answer 55

sutures

Question 56

what are sutures

Answer 56

fibrous joints in the skull limited movement allow growth move together with age - can completely ossify in adults

Question 57

what is the new name of the frontal fontanelle when it is closed

Answer 57

bregma

Question 58

what is the new name of the posterior fontanelle when it is closed

Answer 58

lambda

Question 59

what is the name of the suture in the frontal bone of a fetal skull

Answer 59

metopic suture

Question 60

when does the metopic suture close

Answer 60

2-5 years post birth 10-15% of population will retain it till adulthood - no effect clincally

Question 61

what is the joint of the 2 mandibular bones called in the fetal skull

Answer 61

mental symphsis

Question 62

viscerocranium

Answer 62

facial skeleton

Question 63

neurocranium/calvarium

Answer 63

bones surrounding the brain

Question 64

growth rate variations between the facial skeleton and the neurocranium

Answer 64

Facial skeleton ‘catches up’ with neurocranium in proportions from fetal to adult versions Calvarium to facial proportions are approx. - 8:1 at birth - 4:1 at 5 years - 2.5:1 in adult life After birth facial skeleton grows forwards and downwards with dentition to catch up with neurocranium

Question 65

when is the facial skeleton growth slower than the neurocranium

Answer 65

Proportions are different in foetal skull because brain development most important before birth but skull needs to be small enough for passage through birth canal. Face grows as dentition develop and in response to muscles of mastication - Teeth not required at birth for feeding

Question 66

what is the difference in the angle of the mandible in adult Vs foetal skull

Answer 66

angle of mandible is more obtuse in fetal skull Adult more acute angle due to downward and forward growth of ramus to accommodate the developing dentition

Question 67

what is the Pterion

Answer 67

Closed sphenoidal fontanelle (Important landmark) Coming together of 4 bones Frontal, parietal, sphenoid, temporal

Question 68

why is the Pterion an important landmark

Answer 68

Weak thin bone - middle meningeal artery pass deep to this area Blow here could fracture bone and hit artery

Question 69

when and how does the mastoid process develop

Answer 69

indistinct as an foetus - Mastoid bump behind ear Develop with pull of neck muscles and development of air cells with age

Question 70

tympanic ring

Answer 70

opening to ear external auditory meatus Adult grows outwards so more plate shape

Question 71

when a mental symphysis is open it is

Answer 71

fibrous | early development