growth patterns/timings of head and neck, clinical relevance

Question 1

bones in human head

Answer 1

28 bones

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

Question 2

head to body ratio proportions

Answer 2

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

Question 3

when do sutures fuse

Answer 3

7 yeras

Question 4

what type of growth are surtures

Answer 4

secondary

- repsonding to the brain growing

Question 5

early fusuon of sutures

Answer 5

craniosynotosis
syndromes
- crouzon
- apert
- pfeiffer

Question 6

development of the lower 2/3 face

Answer 6

• downward and downward growth of maxilla and mandible

- elongation of nose

Question 7

what is found at the base of the skul

Answer 7

cranial base synchrondroses

Question 8

crainial base synchondroses

Answer 8

spheno ethmoidal

spheno occuipital

Question 9

spehno ethmpidal

Answer 9

anterior cranial base

follows neurla growth pattern

Question 10

neural growth pattern

Answer 10

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

Question 11

spheno occipital

Answer 11

posterior cranial base

somatic growth pattern (much later on)

Question 12

what is it when synchondroses dont grow

Answer 12

achrondroplasia (dwafism)

Question 13

achrondroplasia

Answer 13

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

Question 14

what is responsible for achrondroplasia

Answer 14

• changes in the genes

Question 15

how does the maxilla grow

Answer 15

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

Question 16

sycondroses growth site type

Answer 16

primary

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

Question 17

why does the maxialla grow width ways

Answer 17

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

Question 18

maxilla bone shaping

Answer 18

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

Question 19

how can orthodontics be used to influence growth of mx

Answer 19

push apart suture to grow the middle of the suture

Question 20

md growth

Answer 20

grows in height and length

Question 21

role of conyde in md growth

Answer 21

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

Question 22

condylar cartilage

Answer 22

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

Question 23

remodelling involved in md formation

Answer 23

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

Question 24

rotation upon growing in md

Answer 24

• 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

Question 25

greater growth in one side of the condyl can lead to

Answer 25

facial asymmetry

Question 26

mx rotation

Answer 26

small but variable rotation

mean 3 degrees anterior, but can be backwards

Question 27

when is soft tissue growth most rapid

Answer 27

around puberty

Question 28

attemtpted mechancisms that control head and face growth

Answer 28

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

Question 29

when should you fit functional applicances

Answer 29

when puberty growth occurs

Question 30

how can you predict when puberty growth will occue

Answer 30

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