Cephalometrics

Question 1

Define the Jugal Process

Answer 1

intersection between the maxillary tuberosity outline and the zygomatic buttress

Question 2

A Large anterior cranial base (S-N) indicates what?

Answer 2

Class II skeletal

Question 3

A large posterior cranial base (S-Ba) indicates what?

Answer 3

Class II skeletal

Question 4

A large cranial base angle (N-S-Ba) indicates what?

Answer 4

Class II skeletal

Question 5

A small or short posterior cranial base (S-Ba) indicates what?

Answer 5

Class III skeletal

Question 6

By what growth process does the cranial base grow?

Answer 6

Endochondral growth

Question 7

What are the radiopaque lines that pass through the orbits in a PA ceph

Answer 7

Greater and lesser wings of Sphenoid

Question 8

What is the oblique line on the orbit (though appears nearly horizontal in lower 1/3 of orbit) in a PA ceph

Answer 8

the Temporal line (petrous part of temporal bone)

Question 9

What is the most common and stable reference line

Answer 9

Frankfort Horizontal

Question 10

What is the Holdaway Ratio

Answer 10

1:1 ratio for distance between L1 to N-B and Pg to N-B

Question 11

What is the Holdaway Ratio used for?

Answer 11

A measurement to evaluate the relative prominence of the mandibular incisors, as compared to the size of the bony chin

Question 12

What is indicated by a short Articulare - Pterygomaxillary Fisure (Ar-PTM) ?

Answer 12

Maxillary retrognathia

Question 13

Basion is found on what bone of the skull

Answer 13

Occipital bone

Question 14

What landmarks define the Anterior Facial Height (AFH): Posterior Facial Height (PFH) ratio?

Answer 14

AFH –> N-Me
PFH –> S-Go

Ratio: AFH/PFH

Question 15

What is the ideal anterior facial height : posterior facial height ratio?

Answer 15

60:40 (AFH/PFH)

Question 16

What landmarks define the Upper Facial height (UFH) : Lower Facial height (LFH) ratio?

Answer 16

UFH –> N-ANS

LFH –> ANS-Me

Question 17

What is the ideal upper facial height : lower facial height ratio?

Answer 17

45:55 (UFH/LFH)

Question 18

Define the Zygomatic Arch (ZA) on a PA ceph

Answer 18

The center point of the zygomatic arch

“Not the Lateral point) = Zygion

Question 19

Define the Bolton Point

Answer 19

the highest point in the concavity posterior of occipital condyle

(The occipital condyle articulates with the superior facets of the atlas (C1) vertebra)

Question 20

Define Basion

Answer 20

The median point of the anterior margin of the foramen magnum

Question 21

Define Opisthion

Answer 21

most posterior point on foramen magnum (opisthios = posterior)

Question 22

Define the Facial Plane

Answer 22

N - Pg

Question 23

What is the Bolton (Broadbent) triangle

Answer 23

Bolton - S - N

Describes growth change between the cranial base and the face

Question 24

Define the Facial Axis

Answer 24

PTM - Gnathion

Question 25

Define the Facial Axis angle

Answer 25

Angle formed between a line from N-Ba and PTM-Gn (Facial axis)
Should be 90 degrees

Question 26

Define the Facial Angle

Answer 26

Angle between FH & N-Pg (88 degrees)

**increases from 8-18 yo

Question 27

What anatomical landmark is noted by PT point

Answer 27

lower lip of Foramen rotundum

Question 28

Describe the best use of Cephalometrics

Answer 28

to determine dental pattern related to skeletal pattern

Question 29

What is the most difficult cephalometric point to identify

Answer 29

A point

Question 30

Define Prosthion

Answer 30

most inferior anterior point of maxillary alveolus between the maxillary incisors