Cephalometrics Flashcards
Space between x-ray tube and film in a cephalometer
5 ft
Center of the pituitary fossa of the sphenoid bone.
Sella turcica
Most anterior point of the frontonasal suture.
Nasion
Lowest point of the inferior margin of the orbit.
Orbitale
Where all the attachments of the nose are.
Anterior nasal spine
Tip of the posterior spine of the palatine bone in the hard palate where the third molars are found.
Posterior nasal spine.
Space between the retromolar tuberosity of the maxilla and the pterygoid process.
Pterygomaxillary fissure
The deepest midline point of the maxilla between the anterior nasal spine and the prosthion.
Subspinale
Subspinale is AKA as what?
Point A
The deepest midline concavity of the mandibular symphysis between the infradentale and pogonion.
Supramentale
Point B is AKA what?
Supramentale.
The most anterior point of the chin at midline.
Pogonion
The lowest point on the chin.
Menton
Most inferior, posterior point on the jaw angle.
Gonion
Midway between the most anterior and inferior points on the bony chin.
Between pogonion and menton.
Gnathion
The most inferior midline point on the mandibular symphysis.
Menton
The most anterior point on the contour of the chin.
Pogonion
Midpoint on the upper edge of the external auditory meatus.
Porion
Lowermost point of the anterior margin of the foramen magnum in the mid-sagittal plane.
Basion
This angle represents the relationship of the maxilla to the cranial base.
SNA Angle
Sella-Nasion-Point A
This angle represents the relationship of the mandible to the cranial base.
SNB Angle.
Sella-Nasion-Point B
Value of SNA
82 +/- 6 degrees
Value of SNB
80 +/- 3 degrees
If SNA is greater than 82, the maxilla is what?
Skeletal class?
Protrusive compared to the cranial Base.
Skeletal Class II
If the SNA is less than 82, the maxilla is what?
Skeletal class?
Retrusive.
Skeletal Class III
If the SNB is greater than 80, the mandible is what?
Protrusive skeletal class III
If the SNB is less than 80, the mandible is what?
Retrusive, skeletal class II
Anterior-Posterior relationship of the maxilla to the mandible.
ANB
ANB Value
2 degrees +/- 3
ANB greater than 2 is what skeletal relationship?
Class II
ANB less than 2 is what skeletal relationship?
Class III
Angular relationship of upper and lower incisor teeth to each other.
Interincisal angle.
Interincisal angle value
130 +/- 6
Interincisal angle less than 130 indicates what?
Protrusive upper/lower incisors (flared out)
Interincisal angle greater than 130 indicates what?
Retrusive upper and or lower incisors.
In ortho, which tooth is number 1? Number 2?
1 = central incisors 2= lateral incisors
and so on…
Angulation between the upper central and NA.
1 to NA
If the 1 to NA angle is 22 degrees, how many mm anterior to the NA line is the central incisor?
4
When the lower central incisor to NB angle is _____ degrees, the most prominent part of the crown usually measures ____ mm in front of NB.
20 degrees
4 mm
Nasion to Porion
Facial plane
Facial plane to Frankfort Plane
Facial Angle
From sella to gnathion.
Y-axis
Y-axis angle
Y-axis to Frankfort plane
Value of Y-axis angle
59 degrees +/- 4
Y-axis angle less than 59 indicates what?
More horizontal growth of the mandible.
Y-axis angle greater than 59 indicates what?
More vertical growth of the mandible.
Mandibular plane
Gonion to Gnathion
Value of the angle between mandibular plane and SN plane is what?
32 degrees.
Patients with a high mandibular plane- SN plane angle have what?
Open bite tendency
Plane from incisors to molars
Occlusal plane
Anterior to Posterior nasal spine
Palatal Plane
Anterior cranial base
Nasion to sella
Posterior cranial base
Sella to Basion
Total anterior facial height.
Nasion to mention
Total posterior facial height.
Sella to Gonion
Upper anterior facial height.
Nasion to Anterior Nasal Spine
Lower anterior facial height.
ANS to menton
UAFH:LAFH = ?
1:1.21
