growth patterns/timings of head and neck, clinical relevance Flashcards

1
Q

bones in human head

A

28 bones

  • 8 cranial
  • 14 facial
  • 6 auditory
  • 1 hyoid
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2
Q

head to body ratio proportions

A
  • 1:4 @ birth (large proportion at birth due to the growth of the brain)
  • 1:8 adults
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3
Q

when do sutures fuse

A

7 yeras

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4
Q

what type of growth are surtures

A

secondary

- repsonding to the brain growing

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5
Q

early fusuon of sutures

A
craniosynotosis
syndromes
- crouzon
- apert
- pfeiffer
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6
Q

development of the lower 2/3 face

A
  • downward and downward growth of maxilla and mandible

- elongation of nose

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7
Q

what is found at the base of the skul

A

cranial base synchrondroses

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8
Q

crainial base synchondroses

A

spheno ethmoidal

spheno occuipital

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9
Q

spehno ethmpidal

A

anterior cranial base

follows neurla growth pattern

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10
Q

neural growth pattern

A

rapid growth early on which then slows, follows growth pattner of briain

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11
Q

spheno occipital

A

posterior cranial base

somatic growth pattern (much later on)

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12
Q

what is it when synchondroses dont grow

A

achrondroplasia (dwafism)

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13
Q

achrondroplasia

A
  • short stature
  • large head as a proportion
  • prominent forehead (frontal bossing)
  • small midface
  • flattened nasal bridge
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14
Q

what is responsible for achrondroplasia

A
  • changes in the genes
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15
Q

how does the maxilla grow

A

downwards and forwards through growth in the cranial base

  • new bone added to both sides of sutures
  • possible secondary growth site following soft tissue growth
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16
Q

sycondroses growth site type

A

primary

- growht of the cartilage is the driving force pushing the face downwards and forwards

17
Q

why does the maxialla grow width ways

A

due to mid palatal suture
fuses around puberty
- areas of new bone addition and resportion

18
Q

maxilla bone shaping

A

floor of nose resorbs
bone added to floor of mouth
appears to move more downwards than forwards
- surface remoddeling occurs in opposite direction to bone translation
reshaping of face as bone moves downwards and forwards

19
Q

how can orthodontics be used to influence growth of mx

A

push apart suture to grow the middle of the suture

20
Q

md growth

A

grows in height and length

21
Q

role of conyde in md growth

A

get longer and remodels
growth in length by cartilage replacement in the condyle
unsure if 1/2 growth site

22
Q

condylar cartilage

A

resembles epiphyseal plate cartilage of long bones
- proliferative cell can differentiate into chrondroblasts
appositional, not proliferative
not organised into parallel colums

23
Q

remodelling involved in md formation

A

resoprtion from the anterior surface
deposition on the posteiror surface
remodeling of the glenoid fossa
growht in height continutes throughout life, lenght ceaces in teens

24
Q

rotation upon growing in md

A
  • remodelling of surfaces of the mandible masks the rotation (masked by surface apposition and resorption)
  • due to differential growth in anterior and posterior face heights
  • internal rotation in core of mandible relative to the cranial base (forwards and upwards)
  • seen by superimposing serial radiographs with implants
25
Q

greater growth in one side of the condyl can lead to

A

facial asymmetry

26
Q

mx rotation

A

small but variable rotation

mean 3 degrees anterior, but can be backwards

27
Q

when is soft tissue growth most rapid

A

around puberty

28
Q

attemtpted mechancisms that control head and face growth

A

1) Remodelling theory
2) sutural theory
3) cartilaginous theory
4) functional matrix theory
5) part counterpart principle
6) servo system theory
non proven

29
Q

when should you fit functional applicances

A

when puberty growth occurs

30
Q

how can you predict when puberty growth will occue

A

Can use hand wrist radiographs
- ulnar sesamoid graph ossifies at start of pubertal growth spurt
Cervical spine maturation
- undertaken on lateral cephalometric radiograph