Cephalometrics involves the scientific measurement of the living head using lateral cephalometric radiographs. It allows orthodontists to analyze skeletal, dental, and soft tissue relationships and compare measurements to norms to diagnose orthodontic issues. Key aspects include standardized positioning of patients using a cephalostat to obtain reproducible lateral x-rays. Tracings of these x-rays are then made and landmarks identified to perform measurements of angles and distances. Common landmarks include nasion, sella, orbitale, and pogonion. Measurements are compared to norms for diagnosis, treatment planning, and evaluation.

1. Cephalometrics
By Dr Chandrika Katti
Reader, Dept Of Orthodontics.
Navodaya Dental College, Raichur.

2. Introduction
• In olden days measurements of head are
made on dry skull.
• But with the advent of cephalometric
radiography measurements can be made on
living skull
• Thus today lateral ceph has became
indispensable to orthodontists as it helps
in growth analysis diagnosis/ treatment
planning ,treatment monitoring & its
evaluation.

3. Definitions
• Cephalometry – Scientific measurement of
dimensions of the ‘living’ head.
• Cephalometric analysis – Process of evaluating
the skeletal, dental, and soft tissue relationships
of a patient by comparing measurements
performed on the patient’s cephalometric tracing
with population norms for respective
measurements, to come to a diagnosis of the
patient’s orthodontic problem

4. History
• By the time x-rays has been discovered by W C
Roentgen in 1895 which expanded the horizon of
craniometry & cephalometry
• 1st x ray picture of skull in lateral view was taken
by Paccini & Carrerain 1922
• In 1931 Hofrath of Germany & Broadbent of USA
simultaneously & independently developed
standardized method for production of
cephalometric radiographs.

5. TYPES OF CEPHALOGRAMS
• Can be of two types
1.Lateral cephalogram: This provides
lateral view of the skull
2.Frontal cephalogram: This provides
antero-posterior view of the skull

6. Lateral and frontal
cephalogram

7. Uses of cephalometry
• For gross inspection, diagnosis
• To describe morphology & growth
• To diagnose anomalies
• To forecast future relationships
• To plan treatment
• To evaluate treatment result
• Research purpose

8. Apparatus
• X ray unit
– X ray tube
– Transformer
– Coolant
– Filter all in a machine housing
• Image receptor system
• Cephalostat

9. Cephalostat
• Head holding device is called cephalostat
• Cephalostat consists of two ear rods that prevent
movement of the head in horizontal plane
• Vertical stabilization is provided by an orbital
pointer that contacts the lower border of the
left orbit
• The upper part of the face is supported by a
forehead clamp positioned above the region of the
nasal bridge

10. Cephalostat
• The distance between X-ray source and
the mid-sagittal plane of the patient is
fixed at 5 feet (152.4 cm)
• Distance betn mid sagittal plane & film is
15cm.
• Thus the equipment helps in
standardization using a constant head
position which helps to compare serial
radiographs

12. Patient positioning
• Pt is positioned in a upright position
with
– FH plane ll to the floor
– Mid saggital plane of patient is
perpendicular to x ray beam & ll to the
film & perpendicular to the floor

13. Tracing technique
• Equipments-
– 8×10 inch film
– Acetate matte tracing paper(0.003” thick &
8×10” size)
– Sharp 3H drawing pencil
– Masking tape
– Geometry box
– View box
– Dental cast
– Tracing template

18. Cephalometric landmarks
Types
– Anatomic
– Derived
 Hard tissue landmarks
 Soft tissue landmarks
Anatomic
These landmarks represent actual anatomic landmarks of the skull.
Derived landmarks
These are obtained secondarily from anatomic landmarks.

19. Cephalometric landmarks
Criteria for landmark selection
• Should be easily identifiable
• Should be uniform in outline and
reproducible
• Should permit valid quantitative
measurements of lines and angles
projected from them.

20. • Landmarks used in cephalometrics
can be classified as:
• Hard tissue landmarks
• Soft tissue landmarks
some are unilateral landmarks and
some are bilateral.

21. Cephalometric landmarks
Unilateral landmarks in lateral cephalograms
• Nasion (Na)- frontonasal suture at its most superior
point on the curve at the bridge of nose
• Anterior nasal spine (ANS)-the most anterior point on
the maxilla at the level of the palate
• Subspinale(“A” point)-the most posterior point on the
curve between ANS and superior Prosthion

22. Cephalometric landmarks
• Superior Prosthion(SPr or Pr)- also called
supradentale. The most anterior ,inferior point on the
maxillary alveolar process, usually found near the CEJ of
the maxillary central incisors
• . Infradentale (Id) or inferior prosthion-The most
anterior superior point on the mandibular alveolar
process,near CEJ of mandibular central incisor.
• Supramentale (“B” point)-The most posterior point of
the bony curvature of the mandible below Infradentale and
above Pogonion

23. Cephalometric landmarks
• Pogonion (Pog)-the most anterior point on
the contour of the chin
• Gnathion (Gn)-The most anterior inferior
point on the lateral shadow of the chin
• Menton (Me)-The lowest point on the
symphyseal outline of the chin

24. Cephalometric landmarks
• Basion (Ba)-The most inferior posterior
point in the sagital plane on the anterior
rim of the foramen magnum
• Posterior nasal spine (PNS)-The most
posterior point on the bony hard palate in
the sagital plane
• Sella (S)-The center of the hypophyseal
fossa

25. Cephalometric landmarks
Bilateral landmarks
Both left and right points are located and used, but some
clinicians use the midpoint of the two.
Following are the points-
– Orbitale (Or)-The lowest point of the bony orbit.
Usually the lowest point on the averaged outline is used for
construction of Frankfurt Plane
– Gonion (Go)-The most posterior inferior point at the angle of
the mandible.
– Condylion (Co)-The most superior point on the condyle of the
mandible.

26. Cephalometric landmarks
• Articulare (Ar)-The intersection of three radiographic
shadows :the inferior surface of the cranial base and the
posterior surface of the necks of the condyles of the
mandible
• Pterygomaxillary fissure (PTM)-Bilateral tear-drop shaped
area of radiolucency ,the anterior shadow of which is the
posterior surfaces of the maxillary tuberosities
• Bolten point -highest point at posterior condylar notch of
occipital bone
• Porion- superior point of external auditory meatus

27. nasion
orbitale
pns ans
Pt A
Pt B
pogonion
gnathion
menton
gonion
articulare
basion
sella

28. Sella
Porion
Gonion
PNS
Menton Gnathion
Pogonion
B Point
A Point
ANS
Orbitale
Nasion
Articular
e
Standard Cephalometric
Landmarks

29. Cephalometric planes/lines
Cephalometric Lines
(Planes)
• Horizontal
• Vertical
Horizontal planes:
• S-N plane :It is the
cranial line between center
of sella and the nasion

30. Cephalometric planes/lines
• Frankfurt
horizontal plane
:The common
tangent to the
upper external
auditory meatus
(at porion) and the
inferior border of
the orbit (orbitale)

31. • Functional
occlusal line
(FOL): A denture
plane bisecting the
posterior occlusion
of molars &
premolars &
extends anteriorly.

32. Cephalometric planes/lines
• Mandibular plane
:several exist, based on
different analysis
1. Tangent to the lower
border of the mandible
(Tweed)
2. A line connecting gonion
and menton (Downs)
3. A line connecting gonion
and gnathion (Steiner)

33. Cephalometric planes/lines
• Bolton’s plane: This
plane connects bolton’s
points posterior to the
occipital condyles and
nasion
Bo
Na

34. Cephalometric planes/lines
• Palatal plane -
line joining
Ans & Pns

35. Cephalometric planes/lines
Basion-Nasion plane: Line
connecting basion and
nasion. Represents cranial
base

36. Cephalometric planes/lines
Vertical planes
• A-Pog line :Line
from Point A to
pogonion

37. • Facial plane :Line from
nasion to pogonion

38. 66
Y Axis
Ptm point to Gnathion

39. Soft tissue landmarks
• G-Glabella-most prominent point in the mid
sagittal plane of forehead
• N’-Soft tissue nasion-pint of greatest concavity in
the midline betn forehead & nose
• P-Pronasale-most prominent point on ant point of
nose
• Sn-subnasale-point at which nasal septum merges
with upper lip
• SLS-superior labial sulcus-point of greatest
concavity in midline of upper lip
• Ls-labrale superius-most anterior point of upper
lip

40. Soft tissue landmarks
• Stms-stomion superius-lowermost point on
vermillion of upper lip
• Stmi-stomion inferius-the uppermost point on the
vermillion of the lower lip
• St- stomion-mid point betn stms & stmi
• Li-labrale inferius-median point in the lower
margin of the lower membranous lip
• Ils-inferior labial sulcus-point of greatest
concavity in the midline of lower lip
• Pog’-soft tissue pogonionmost anterior point on
the chin
• Me’-soft tissue menton-lowest point on contour of
soft tissue chin

41. SOFT TISSUE NASION
PRONASALE
SUB NASALE
SUPERIOR LABIAL SULCU
LABRALE SUPERIUS
STOMION
LABRALE INFERIUS
INFERIOR LABIAL SULCUS
SOFT TISSUE POGONION
SKIN GNATHION
GLABELLA

42. Problems and limitations
• It is a two dimensional representative of
three dimensional structures.
• Problems in orientation of patient while
procuring radiograph.
• Difficulty in location of landmarks
precisely.