Ceph Skeletal AP Measurements Flashcards
SNA Angle
Lines: Sella-Nasion, Nasion-A Point
Measure: inner angle between lines
Indicates: Anteroposterior position of Maxilla
Norm: 82 +/- 4
SNB Angle
Lines: Sella-Nasion, Nasion-B Point
Measure: Inner angle between lines
Indicates: Anteroposterior position of mandible
Norm: 80 +/- 4
WITS Analysis
Lines: Occlusal plane, Perpendicular point between A point and B point
Measure: between lines
Indicates: AP Maxillary/mandibular relation
Norm: Male = -1mm, Female = 0mm
A Point to Nasion Perpendicular
Lines: Frankfort Horizontal, N Perpendicular
Measure (mm): to A point, at right angle to N perpendicular
Indicates: anteroposterior position of maxilla
Norm: +1mm +/- 2.5
Pogonion to Nasion Perpendicular
Lines: Frankfort horizontal, N Perpendicular
Measure: right angle to N Perp, to pogonion
Indicates: anteroposterior position of mandible
Norm:
Males = 0mm +/- 2mm
Females = -2mm +/- 2mm
Maxillary AP Excess
(PROTRUSION)
Norm = 82 +/- 4
Between 1st and 2nd SD
Mild AP excess (this photo = SNA = 89)
Maxillary AP excess #2
(PROTRUSION #2)
A point to Nasion Perpendicular
Norm = +1mm +/- 2.5
This picture: A-N Perp = 5.5 mm
Between 1st and 2nd SD
Mild maxillary AP excess
Mandibular AP Deficiency
(RETRUSION)
SNB Angle Norm = 80 +/- 4mm
In this = SNB = 75 degrees
Between 1st and 2nd SD
Mild Mandibular AP Deficiency (retrusion/retrognathia)
Mandibular AP Deficiency #2
(RETRUSION #2)
Pogonion to Nasion Perpendicular
Norm = -2mm +/- 2 (female)
This picture: Po-N Perp = -8mm
between 2nd and 3rd SD
Moderate mandibular AP deficiency
Maxillary AP Deficiency
(RETRUSION)
SNA Norm = 82 +/- 4
This pic = 75
Between 1st and 2nd SD
Mild AP deficiency
Some mandibular excess
Maxillary AP Deficiency #2
(RETRUSION #2)
A point to Nasion Perpendicular
Norm = +1 mm +/- 2.5
This pic = AP Perp = -6mm
Between 2nd and 3rd SD
Moderate maxillary AP deficiency
Mandible slight AP excess
Mandibular AP Excess
(PROGNATHIC)
SNB Angle Norm = 80 +/- 4
This pic = SNB = 95
3+ SD
Severe Mandibular AP Excess
Mandibular AP Excess #2
(PROGNATHIC #2)
Pogonion to Nasion Perpendicular
Male Norm = 0 +/- 2 mm
This pic: Po-N Perp = +21 mm
3+ SD
Severe mandibular AP excess (holy shit)
Condylion to A Point
Lines = Co-A
(Measure between Co and A point)
Indicates = AP length of maxilla
Norm = use chart; depends on AP position of maxilla; can be used to find norm for mandibular length and vertical
Condylion to Gnathion
Lines = Co-Gn
(Measure between Co to Gn)
Indicates = AP length of mandible
Norm = use chart; found in chart relative to maxilla; can be used to find norm for maxillary length
If you want to quiz yourself on the chart - flip over
