Ceph Planes

Question 1

Sella Nasion Plane

Answer 1

Between Sella and Nasion

Anterior Cranial Reference Plane

Anterior cranial growth completed by 7 years

Question 2

Frankfort Horizontal Plane

Answer 2

Inferior border of soft tissue chin

Difficult to find consistently

Located by bisecting angle between: N-Po plane, Mandibular Plane

Question 3

Mandibular Plane

Answer 3

Between Gonion and Menton

Reference for lower border of mandible

May reflect musculature and face height

Question 4

Nasion Perpendicular Plane

Answer 4

Line drawn through Nasion

Perpendicular to Frankfort Horizontal Plane

Reference for antero-posterior position of maxilla and mandible

Question 5

Basion-Nasion Plane

Answer 5

Between Basion and Nasion

Represents entire cranial base

Divides face from cranium

Question 6

Facial Axis Plane

Answer 6

Between pterygoid point and Gnathion

Indicator of skeletal vertical (?)

In growing individual = normal mandibular growth occurs along line

Question 7

Occlusal Plane

Answer 7

Line drawn between overlapping cusps

• Of 1st molars
• Of 1st bicuspids

Represents posterior plane of occlusion