Practical cephalometric tracing

Practical Cephalometric Tracing
Instructor;
DR TED NAING
MDC licence no.THA 1067
Mandalay,Myanmar
Dr Ted's Orthodontic Study
Club,Mandalay,MYANMAR

Profile view or lateral view of the skull

A
lateral
cephalometric
film

Three orientation crosses

Cephalometric landmarks
Midline structures
• S
• N
• ANS
• PNS
• Me
• A point
• B point
• Pog
• Gn
• UI
• LI
Bilateral structures
• Ptm
• Go
• Po
• Or
• Co
• Ar

‘S’ point; sella tuccica
Outline the contour of pituitary gland fossa.
Mark the geometric centre of the circular
outline of the arc of sella tuccica.

‘N’point;nasion
• Find the junction of frontal bone and nasal
bone outline.
• Point the junction of fronto-nasal suture at
just superior and anterior most point.

‘ANS’;anterior nasal spine
• Find the bony spur at the junction of nose and lip.
• Draw the outline of vomer and palatine bone.
• Anteriormost part of the naso-palatine bone
outline is anterior nasal spine.

‘Ptm’;pterygo maxillary fissure
• Pterygo-maxillary fissure is a reverse tear drop
bony shadow above the ramus of mandible.
• It was formed by the medial and lateral pterygoid
plate on both side.
• There is left and right ‘Ptm’ shadows in a Ceph.

‘PNS’;posterior nasal spine
• Posterior nasal spine is the posterior end of
hard palate;i.e;vomer and palatine bone.
• It can be found at just immediate below to
‘Ptm’,where the nasal floor and bony hard
palate meet.

‘Me’;menton
• Draw an outline of symphysis menti,
(mandibular symphysis).
• Menton is the inferiormost point of the bony
chin.

Averaging of bilateral landmarks

‘Go’;gonion :angle of the mandible
• Draw the outline of the
mandibular ramus and body.
• Note the average outline of
the both left and right
contour of the mandible.
• Gonion is at the meeting
point of tangent lines drawn
from posterior border of the
ramus and inferior border of
the mandibular body.

‘Or’;Orbitale
• Superior border of Infra-Orbital rim.(bilateral
structure)
• There is left and right shadows of two orbits.
• Draw an outline of the lateral border of the orbit till
to the inferior contour as reverse ‘J’ shape outline.
• The smaller the shadow ,the structure will more
nearer to the film and being less magnified.(left
infra-orbital rim)

‘Po’;porion;external auditory meatus
metal rings on the ear rods of cephalostat make both
shadows of left and right ear orifices(external auditory
meatus).
The smaller circle is the shadow of closer site of the
ear(mostly left site of the head).
Porion can be pointed at the superior margin of the
smaller circle whatever the another circle(right ear) is
located.

‘A’point;
representative point for maxilla
• The most concave point on the
anterior outline of bony maxillary
alveolus.
• Start from ANS along the anterior
outline downside.
• Trace along the anterior outline from
the alveolar margin of upper central
incisor.
• Vertical imaginary tangent to the
concavity of maxillary alveolaus

‘B’point;
representative point for mandible
• The most concave point
on the anterior contour
of alveolar process of
symphysis menti.
• Imaginary vertical
tangent to the concavity
of mandibular alveolar
process

‘Pog’;pogonion
• Anterior most point of the
bony chin
• Make imaginary vertical
tangent of the most
convex portion of
symphysis menti
anteriorly.

Outline of the maxillary and
mandibular central incisors
Maxillary U1
• Draw an outline of the U1
with a pencil or a template
Mandibular L1
• Draw an outline of the L1
with a pencil or a template

Cephalometric Analyses
• 1.methodological
• 2.normative classification
• 3.according to area of analyses

Methodological analyses
• 1.1.Angular analyses
• 1.1.1.dimensional analyses; considers various angles in
isolation comparing them to standard norms. Eg. Down’s analysis
• 1.1.2.proportional analyses; based on comparison of the
various angles to establish relation between the separate parts of the
facial skeleton.e.g.: Koski’s analysis
• 1.1.3.analysis to determine position; angular
measurements can also be used to determine position of
parts of facial skeleton. Eg. SNA and SNB angles give relation
between maxillary and mandibular bases and the cranial base.

Methodological analyses cont;d
• 1.2.Linear analyses
Orthogonal analyses –a reference plane is established with various
reference points projected onto it perpendicularly after which
distances between the projections are measured.
Total orthogonal analysis:
• a)Geometrical eg. De coster
• b)Arithmetical: reference points projected onto horizontal and
vertical planes and distances between them measured. Eg. Cobens
Partial orthogonal analysis: involves assessment of only part of skull.
Archial analysis: which reference points are not projected
perpendicularly ,but by drawing arcs with the help of compass. eg:
Sassouni analysis

• Linear analyses (cont;d)
Dimensional linear analyses
• - Direct method which gives distance between two reference
lines eg.Length of mandibular base
• - Projected method which determines distance between
certain reference pts that have been projected onto a
reference plane.
Proportional linear analyses: based on relative rather than
absolute values, measurements compared to each other than to
norms

2.Normative classification
according to concepts on which norms have been based
on
Mononormative analyses- averages are norms
• Arithmetical norms: figures based on angular, linear ,
and proportional measurements.
• Geometrical norms: average tracings on a transparent
sheet assessment consists of comparing these with the
case under analysis .
Multinormative analyses: whole series of norms are
used including age &sex.
Correlative analyses- to asses individual variations of
facial structures ,to establish their mutual relationship

According to area of analyses:
Dento-skeletal analyses : analyze teeth and
skeletal structures .
Soft tissue analyses : may involve whole profile
or certain structures
Functional analyses: functional relations such as
occlusion to interocclusal space relationship

Compiling Analytic Information
Anthropometry of the face and cephalometric analysis of
the facial skeleton are disciplines that complement each
other in the evaluation of deformities and surgical
planning of aesthetic, dentofacial, and craniofacial
procedures.
One's subjective clinical assessment and the patient's
desires must also be considered in the overall treatment
plan.
However, the ability to perform a thorough facial and
cephalometric analysis can be useful when there is an
unclear etiology to a patient's perceived deformity.

Tweed triangle

Moorees mesh diagram

Jacobson’s proportionate template

Ricketts ‘Ba-Na line

Sum of posterior angle of Jarabak

Mc Namara’s
maxillary and mandibular length

Bjork’s dento-basal relation

Schopf(1982) developed a graph to access
facial configurations.

THANK YOU!

Practical cephalometric tracing

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