Test #1

Question 1

Rule of Fifths

Answer 1

lateral extent of the eyes to ears
=
width of eyes
=
width of nose

Question 2

Vertical proportions-rules of Thirds

Answer 2

• upper 1/3 hair to glabella
• middle 1/3 glabella to subnasale
• lower 1/3 subnasale to menton

Question 3

lower face divisions

Answer 3

subnasale to menton:

• 1/3-subnasale to stomion
• 2/3-stomion to menton

Question 4

pogonion

Answer 4

anterior of chin

Question 5

menton

Answer 5

inferior of chin

Question 6

gnathion

Answer 6

anterior-inferior of chin

Question 7

gonion

Answer 7

posterior-inferior of body of mandible

Question 8

orbitale

Answer 8

inferior of orbit

Question 9

porion

Answer 9

auditory meatus

Question 10

what are the different reference planes?

Answer 10

sella-nasion (anterior cranial base)

• frankfort horizontal (representing natural horizontal)
• occlusal plane
• mandibular plane (Go-Gn)

Question 11

soft tissue points:

Answer 11

Glabella (G)
Subnasale (Sn)
Pogonion (soft tissue)

Question 12

Direct Genetic control theory

Answer 12

• bone growth in controlled directly via genetics. (no matter what the environment, bone will grow to a predetermined size and shape)
• Sicher’s Theory of Sutural Growth (sutures as growth centers

Question 13

epigenetic theory

Answer 13

• there is genetic control of carilage growth with consequent passive displacement of bone.
• Scott’s cartilaginous Growth Theory: gowth of cartilage genetically determined and bone responds to this

Question 14

Environmental Control Theory

Answer 14

Bone and cartilage growth are both controlled by signals from other tissues (soft tissues and muscle) thereby growing in response to the environment
-Moss’ functional matrix theory: growth of the face is in response to environmental influences of functional demands and that growth of bones would be mediated via soft tissues and muscle forces

Question 15

Cranial bones form by what mechanism?

Answer 15

-intramembranous formation and separate in response to growth of the brain with bone filling in as sutures separate

Question 16

The cranial base: the bones that make it, and it’s growth mechanism

Answer 16

• the occipital (base), the sphenoid and the ethmoid bones,
• grows via endochondral ossification (true growth centers)
• it’s less responsive to the growth of the brain

Question 17

what are the synchondroses of the cranial base?

Answer 17

• spheno-ethmoid
• spheno-occipital
• inter-sphenoid

Question 18

growth of the maxilla

Answer 18

• migration away from the cranial base with apposition at the sutures
• extensive apposition and resorption

Question 19

nasomaxillary complex

Answer 19

• intramembranous formation
• until age 7 major contribution to growth is passive displacemnt of nasomaxillary complex downward and forward due to growth of cranial base

Question 20

growth

Answer 20

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