This document describes Dr. Duane Grummons' posteroanterior (PA) cephalometric analysis for evaluating facial asymmetry. The analysis involves constructing reference lines and planes to compare bilateral landmarks and structures. Measurements are made of linear distances, angles, ratios and volumetric comparisons. The comprehensive analysis evaluates multiple structures and parameters while the summary analysis focuses on key dental and skeletal factors. The analysis is useful for orthodontic/surgical treatment planning by identifying asymmetries and extent of movements needed for symmetry.
2. Introduction
• The PA cephalogram offers an effective tool in
evaluating the craniofacial structures in transverse and
vertical dimensions.
• It allows us to look at the facial skeleton in relative view
of the right-left face and upper-lower face.
3. Frontal and asymmetry information is vitally important in:
• Orthodontic surgery planning (lateral and frontal VTOs);
• Differential tooth eruption with segmental TMJ splint therapy;
and
• Functional jaw orthopedics including three dimensional
improvements in facial or dental proportions or symmetry.
4. Cephalometric set-up
• A headholder or a cephalostat that can be rotated 90° is used,
so that the central X-ray beam penetrates the skull of the
patient in a posteroanterior direction and bisects the
transmeatal axis perpendicularly.
• The standard distance from X-ray source to patient is 5 feet
(152.4 cm)
• The tip of the nose and forehead should lightly touch the
cassette and the FHP should be parallel to the floor
5. PA Ceph Analysis
• Most of the posteroanterior cephalomctric analyses
described in the literature are quantitative, and they
evaluate the craniofacial skeleton by means of linear
absolute measurements of:
• Width or height (Solow, 1966; Ricketts et al, 1972;
Ingerslev and Solow, 1975; Movers et al, 1988; Nakasima
and Ichinose, 1984; Grummons and Kappeyne van de
Coppello, 1987; Athanasiou et al, 1992);
6. • Angles (Ricketts et al, 1972; Svanholt and Solow, 1977;
Droschl, 1984; Grummons and Kappeyne vande Coppello,
1987; Athanasiou et al, 1992);
• Ratios (Costaras et al, 1982; Grummons and Kappeyne van
de Coppello, 1987; Athanasiou et al, 1992); and
• Volumetric comparison (Grummons and Kappeyne van de
Coppello, 1987).
7. • The different structures of the craniofacial
complex can also be analysed using
qualitative methods (Sollar, 1947;
Grayson et al, 1983; Proffit, 1991).
• The analysis proposed by Grummons and
Kappeyne van de Coppello (1987)
contains quantitative assessment of
vertical dimensions and proportions.
8.
9. DR. DUANE GRUMMONS
DDS MSD
“Top Orthodontist” by
Orthopedic Products Magazine –
2012
American Board Certified in
Facial Orthopedics and
Orthodontics
10. • Born- Sept 14, 1944
• DDS – Marquette Univ School of Dentistry,
Milwaukee,Wisconsin(1970)
• MSD – Fairleigh Dickinson Dept of Speciality
Orthodontics (1974)
• Faculty – Loma Linda Dept of Facial
Orthopedics and Orthodontics (25 years)
• Military – US Air Force Captain
• Innovator of orthodontic and facial
orthodontic therapies
11. Grummons Analysis
• This is a comparative and quantitative
posteroanterior cephalometric analysis.
• It is not related to normative data.
• The analysis is presented in two forms:
– The Comprehensive frontal asymmetry analysis
– The Summary frontal asymmetry analysis.
13. • Crista Galli(Cg) : located on the midpart of the ethmoid
bone. Constricted part is marked Cg. Upper part of crista
galli is superimposed by frontal crest. Lower part leads
to perpendicular plate of ethmoid bone
• Anterior Nasal Spine (ANS) : located in the central part
of piriform aperture
• Nasal cavity(NC)- Nasal cavity at widest point
• J point : Intersection of lower border of zygomatic
process and outer surface of maxillary tuberosity
14. • Menton is the most inferior midpoint of the chin on the
outline of the mandibular symphysis
• Frontozygomatic Suture(Z) is the most medial and
anterior point of each frontozygomatic suture at the level
of the lateral orbital rim
• Zygomatic Arch (ZA) : Cross section of zygomatic arch
• A1-Upper Central Incisor Edge
• B1- Lower Central Incisor Edge
15. • Condylion (Co) is the most postero-superior point of
each mandibular condyle in the sagittal plane.
• Antegonial notch (Ag)-The highest point of the notch
or concavity of the lower border of the vertical
mandibular ramus where it joins the body of the
mandible
16.
17. Tracing Suggestion
Before tracing the various skeletal and dental structures
of a posteroanterior cephalogram, the examiner must
ensure that the head position and the intermaxillary
occlusal relationships that appear in the X-ray do not
differ significantly from those identified during the
clinical or photographic evaluation of the patient or
those found in the analysis of dental casts.
18. To ensure correct head tilt
• Check the patient from side to see the Frankfort
Horizontal Plane ( from infraorbital margin to
external auditory canal) is close to horizontal
• Another technique- Plumb Line
Suspend a plumb line, made from thin wire and a
weight, from the X-ray cassette. This Line will then
appear as a true vertical reference line on
radiographs
19. Midsagittal Reference Line
• A midsagittal reference line (MSR)
is constructed from crista galli
(Cg) through the anterior nasal
spine (ANS) to the chin area
• An alternative way of constructing
the MSR line, if anatomical
variations in the upper and middle
facial regions exist, is to draw a
line from the midpoint of Z-plane
either through ANS or through the
midpoint of both foramina
rotundum (Fr-Fr line)
20. MSR LINE
• Midsagittal reference line permits the clinician to compare
right and left sides for transverse and vertical variations,
disproportional relationships, and assymetry
• Look down the tracing (MSR) at the midline
• If the horizontal lines donot match or intersect at MSR, one
side is different than the other by millimeter difference
• Locate the chin and measure its deviation from MSR
22. Horizontal Planes
• Four planes are drawn to show the degree of
parallelism and symmetry of facial structures
23. – One connecting the medial
aspects of the
zygomaticofrontal sutures
(Z);
– One connecting the centres
of the zygomatic arches
(ZA);
– One connecting the medial
aspects of the jugal
processes (J); and
– One parallel to the Z-plane
through menton.
Construction of Horizontal Planes
24.
25. Mandibular Morphology
Analysis
• Leftsided and rightsided triangles
are formed between the head of
the condyle (Co) to the antegonial
notch (Ag) and menton (Me).
• A vertical line from ANS to Me
visualizes the midsaggital plane in
the lower face.
26.
27. PARAMETE
RS
RIGHT SIDE LEFT SIDE Difference
Co-Ag linear 69mm 70mm 1
Ag-Me linear 54mm 41mm 13
Co-Me linear 119mm 100mm 19
<Co-Ag-Me 123o 1300
28. Volumetric Comparison
• Four connected points determine
an area, and here a connection is
made between the points:
– condylion (Co);
– antegonial notch (Ag);
– menton (Me)
– the intersection with a
perpendicular from Co to MSR
• The two polygons (leftsided and
rightsided) that are defined by
these points can be superimposed
with the aid of a computer
program, and a percentile value of
symmetry can be obtained
29.
30. Maxillomandibular
Comparison of Asymmetry
• Four lines are constructed,
perpendicular to MSR, from Ag and
from J, bilaterally.
• Lines connecting Cg and J, and
lines from Cg to Ag, are also drawn.
• Two pairs of triangles are formed in
this way, and each pair is bisected
by MSR. If symmetry is present, the
constructed lines also form the two
triangles, namely J-Cg-J and Ag-Cg-
Ag.
31.
32. Linear Asymmetry
Assessment
• The linear distance to MSR and
the difference in the vertical
dimension of the perpendicular
projections of bilateral landmarks
to MSR are calculated for the
landmarks Co, NC, J, Ag, and Me.
• With the use of a computer, left
and right values and the vertical
discrepancies between bilateral
landmarks can be listed
34. Parameter Right side Left side Difference
Co-MSR 54 52 2
Nc-MSR 18 12 6
J-MSR 34 29 5
Ag-MSR 43 37 6
35. Maxillomandibular
relation
• During the X-ray exposure,
an 0.014-inch (0.356-cm)
Australian wire is placed
across the mesioocclusal
areas of the maxillary first
molars, indicating the
functional posterior occlusal
plane.
• The distances from the
buccal cusps of the maxillary
first molar to the J-
perpendiculars are
measured.
36. • Lines connecting Ag-Ag
and ANS-Me, and the
MSR line, are also drawn
to reveal dental
compensations for any
skeletal asymmetry, the
so-called
maxillomandibular
imbalance.
38. Frontal Vertical Proportion
Analysis
• The following ratios are
taken into consideration (Al:
upper central incisor edge,
Bl: lower central incisor
edge):
– upper facial ratio - Cg-ANS:Cg-
Me
– lower facial ratio - ANS-Me:Cg-
Me
– maxillary ratio - ANS-A1:ANS-
Me
39. – total maxillary ratio –
ANS-Al:Cg-Me
– mandibular ratio –
Bl-Me:ANS-Me
– total mandibular ratio –
Bl-Me:Cg-Me
– maxillomandibular ratio –
ANS-Al:Bl:Me
– These values can be compared
with common facial esthetic
ratios and measurements
40. upper facial ratio - Cg-
ANS:Cg-Me= 55/124
=44.35%
lower facial ratio - ANS-
Me:Cg-Me= 69/124=55.6%
maxillary ratio - ANS-
A1:ANS-Me=27/69=39.1%
total maxillary ratio - ANS-
Al:Cg-Me= 27/124=21.77%
mandibular ratio - Bl-
Me:ANS-Me=33/69=47.8%
total mandibular ratio - Bl-
Me:Cg-Me= 33/124=26.6%
maxillomandibular ratio -
ANS-Al:Bl:Me=
27/33=81.8%
41. upper facial ratio –
Cg-ANS:Cg-Me
44.35%
lower facial ratio –
ANS-Me:Cg-Me
55.6%
maxillary ratio –
ANS-A1:ANS-Me
39.1%
total maxillary ratio-
ANS-Al:Cg-Me
21.77%
mandibular ratio –
Bl-Me:ANS-Me
47.8%
total mandibular ratio -
Bl-Me:Cg-Me
26.6%
maxillomandibular ratio-
ANS-Al:Bl:Me
81.8%
42. Rocky Mountain Data Systems (Los Angeles, CA, USA).
Shown are Grummons frontal/partial (2), and Grummons
frontal/complete.
45. FACIAL ASYMMETRY::
• FIVE IMPORTANT QUESTIIONS
1.Is the maxillary width equally wide?
2. Is the occlusal plane level?
3. Is the maxillary dentition centered with the facial
skeletal midline?
4. Are the maxillary and mandibular midlines
aligned?
5. Is the chin location centered, or nearly so?
46. • The Comprehensive Frontal Assymetry Analysis consists of
all the data described and three tracings
• The horizontal planes, mandibular morphology, and maxillo-
mandibular comparisons have been combined to produce the
Summary Facial Asymmetry Analysis, which by intention
displays less data.
• This provides a practical summary of the patient's frontal
asymmetry, emphasizing key dentoalveolar and skeletal
factors that influence treatment decisions
49. (c) overlay tracing with leveled occlusal
plane reveals extent of osteotomy
required to create
symmetric maxillary component;
(d) locate incisors to treatment
objective and center on facial midline
(MSR); (e)
trace key landmarks and lines on overlay
tracing
50. (f) position mandibular overlay optimally
to level horizontally Ag-gA
plane with chin at midline (decision about
possible separate chin osteotomy may be
needed to reach best-fit occlusion
and a centered chin in the final result);
(e)trace key landmarks and lines on
overlay tracing;
51. (g) when occlusal plane is set level, mandibular
Ag-gA plane and chin are
still asymmetric;
(h) symmetry of lower facial two-thirds exists,
as does molars best-fit occlusion;
52. (i) if mandible is
positioned to best symmetry, then molars are not
reaching on the short side (these can be erupted
and leveled postoperatively
(j) if chin is more than 3 mm off facial midline (MSR),
then consider chin relocation for centering and
lower facial third proportionality (side overlay tracing so
Me region is on MSR and the contour of chin border is
balanced);
53. (k) measure/record chin reference point changes
to predict millimeters of movement laterally,
rotationally,
and vertically;
(l) symmetric outcome predicted and summary
of treatment changes and extent/location of
surgical
moves are known and calculated
54. Conclusion
• The Simplified Grummons Frontal Analysis provides a practical
method to determine conditions, locations, and extent of facial
assymetry using hard tissue analysis
• It is of greatest clinical value when integrated with data from
• lateral and submental vertex radiographs
• Head rotation and improper construction of MSR can reduce
the effectiveness of this analysis.
• In addition, measurements are subject to distortion
55. References
• A Frontal Asymmetry Analysis- Duane C. Grummons, DDS,
MSD ;Martin A. Kappeyene Van De Coppello ; JCO Volume 1987
Jul(448 - 465)
• Frontal Cephalometrics:Practical Applications, Part 1 ;World
J Orthod 2003;4:297-316
• Frontal Cephalometrics:Practical Applications, Part 2 ;World
J Orthod 2004;5:99-119
• Orthodontic Cephalometry by Athanasios E Athanasiou
• Contemporary Cephalometric Radiography - Kunihiko
Miyashita
