Cephalometric landmarks

BDS [Orthodontics] course

1. CEPHALOMETRICS
PROF (Dr.) SAIBEL FARISHTA

2. CEPHALOMETRICS
DEFINITION
Scientific study of the measurementof
the head.
CEPHALOMETRIC RADIOGRAPHY is a
standardized method ofproduction of
skull radiographs,which are useful in
making measurements of the cranium and
the orofacial complex.The radiograph thus
obtained is called a cephalogram.

3. DISCOVERED BY-
IN 1931,HOFRATH IN GERMANY AND
BOARDBENT IN U.S.A
Provided a standardized
cephalometric technique using a high
power x-ray machine and a head
holder called a CEPHALOSTAT.

4. TYPES OF CEPHALOGRAMS
LATERAL FRONTAL

5. WHY CEPHALOMETRICS?
Aids in orthodontic diagnosis by enabling
the study of skeletal,dental and soft tissue
structures of the craniofacial region.
Aids in establishing the facial type.
Helps in the classification of skeletal and
dental abnormalities.
Helps in treatment planning.

6. Aids in evaluating the treatment results
and recognizing changes brought about by
treatment.
Aids in predicting growth changes and
changes associated with surgical
treatment.
Study of relapse in orthodontics.
Valuable aid in research work.

7. OBTAINING A CEPHALOGRAM
CEPHALOMETRIC EQUIPMENT
CEPHALOSTAT,X-RAY SOURCE & A
CASETTE HOLDER.
Cephalostat-2 ear rods-prevent movement
of the head in the horizontal plane.
Vertical stabilization of the head-orbital
pointer that contacts the lower border of
the left orbit.

8. The upper part of the face is supported
with the help of a forehead clamp which is
positioned above the region of the nasal
bridge.
The distance between the x-ray source
and the midsagittal plane of the patient is
5 feet.

9. CEPHALOMETRIC LANDMARKS
LANDMARK-Is a point serving as a guide
for measurement.An ideal landmark is
located reliably on the skull and behaves
consistently during growth.
It should not be assumed that all the
landmarks are equally reliable and valid.
The reliability,reproducibility and
dependability of a landmark is affected by-

10. #The quality of the cephalogram.
#The experience of the tracer.
#Confusion with other landmarks.
The cephalometric landmarks should have
the following attributes-
A) Should be easily seen on the radiograph.
B)Uniform in outline.

11. C)Should be easily reproducible.
D)Landmarks should permit valid
quantitative and qualitative measurements
of lines and angles projected from them.
E)Measurements should be amenable to
statistical analysis.

12. CLASSIFICATION OF LANDMARKS
1)ANATOMIC LANDMARKS
2)DERIVED LANDMARKS
3)UNILATERAL LANDMARKS
4)BILATERAL LANDMARKS
5)IMPLANTS

13. ANATOMIC LANDMARKS
They represent actual anatomic structures
on the skull e.g. ANS,Na
DERIVED LANDMARKS
These are obtained secondarily from
anatomic structures in a
cephalogram.e.g.Ar(Articulare),Ptm(Pteryg
omaxillary fissure)

14. IMPLANTS
They are artificially inserted radio opaque
markers, usually made of inert metal.
They are ‘PRIVATE POINTS’ and their
position can vary from subject to subject.
They are ideal for longitudinal studies on
the same subject.

15. UNILATERAL LANDMARKS
NASION-The most anterior point midway
between the frontal and the nasal bones
in the frontonasal suture.

16. ANTERIOR NASAL SPINE/ANS
It is the tip of the sharp bony process of
the maxilla in the midline.

17. PROSTHION
The lowest and the most anterior point on
the alveolar process in the median plane
between the central incisors.

18. SUBSPINALE/POINT A
It is the deepest point in the midline
between the ANS and the alveolar crest,
between the two central incisors. It is also
called as subspinale.
Pink dot-pt.A

19. INFRADENTALE/(Id)
The highest and the most anterior point in
the alveolar bone in the midline between
the lower central incisors.
Bluedot-(Id)

20. SUPRAMENTALE/Pt.B
It is the deepest point in the midline
between the alveolar crest and the mental
process.
Pink dot-pt.B

21. POGONION(Pog)
It is the most anterior point of the bony
chin in the median plane.
Red dot-(Pog)

22. MENTON(Me)
It is the most inferior midline point on the
mandibular symphysis.
Yellow dot-Me

23. GNATHION(Gn)
It is the most antero -inferior point on the
symphysis of the chin. It is constructed by
intersecting a line drawn perpendicular to
the line connecting menton and pogonion.
Orange dot-(Gn)

24. BASION(Ba)
It is the median point on the anterior
margin of foramen magnum.

25. POSTERIOR NASAL SPINE(PNS)
The most posterior point in the bony hard
palate in the sagittal plane.
Marks the distal limit of the maxilla.

26. SELLA(S)
The point representing the midpoint of
sella tursica.

27. GLABELLA:It is the most prominent point
of the forehead in the mid-saggital plane.
SUBNASALE:The point where the lowest
border of the nose meets the outer
contour of the upper lip.
●G
●Sn

28. BILATERAL LANDMARKS
1)ORBITALE(Or)
The lowest point on the inferior bony
margin of the orbit.

29. G0NION
It is a constructed point at the junction of
ramal plane and mandibular plane.

30. CONDYLION/(Co)
The most superior point on the head of
condyle.

31. ARTICULARE/(Ar)
It is a point at the junction of the posterior
border of the ramus and inferior border of
the basal part of the occipital bone.
Blue dot-(Ar)

32. PTERYGOMAXILLARY POINT/Ptm
It is the intersection of the inferior border
of foramen rotundum with the posterior
wall of pterygomaxillary fissure.
It is a bilateral tear drop shaped area of
radiolucency.

33. PORION/(Po)
The highest bony point on the upper
margin of the external auditory meatus.

34. BOLTON POINT
The highest point at the posterior condylar
notch of the occipital bone.
Bo

35. THE KEY RIDGE-The lowest most point
on the contour of the anterior wall of the
infratemporal fossa.
CHELION:It is the lateral terminus of the
oral slit on the outer corner of the mouth.

36. LINES AND PLANES IN
CEPHALOMETRY
Cephalometrics makes use of certain lines
or planes. These lines are obtained from
connecting two landmarks.
Based on their orientation the lines or
planes are classified into:
Horizontal and vertical planes.

37. HORIZONTAL PLANES
1)S.N.PLANE-It is the cranial line between
the center of sella tursica and the anterior
point of the fronto nasal suture(nasion).
It represents the anterior cranial base.

38. FRANKFORT HORIZONTAL PLANE
This plane connects the lowest point of
the orbit(orbitale)and the superior point of
the external auditary meatus(porion).

39. OCCLUSAL PLANE
It is a denture plane bisecting the
posterior occlusion of the permanent
molars and premolars(or deciduous molars
in mixed dentition)and extends anteriorly.

40. MANDIBULAR PLANE
Several mandbiular planes are used in
cephalometrics,based on the analysis being
done. The most commonly used ones are-
TWEEDS-Tangent to the lower border of
the mandible.
STEINERS-A line connecting gonion and
gnathion.
DOWNS-A line connecting gonion and
menton.

41. PALATAL PLANE
It is a line linking the anterior nasal spine
of the maxilla and the posterior nasal
spine of the palatine bone.

42. BASION-NASION PLANE
Line connecting the basion and nasion.
Represents the cranial base.

43. VERTICAL PLANE
A-POG LINE: It is a line from point A on
the maxilla to pogonion on the mandible.

44. FACIAL PLANE
It is a line from the anterior point of the
frontonasal suture (nasion)to the most
anterior point of the mandible(pogonion).

45. BOLTON’S PLANE
This is a plane that connects the Bolton's
points posterior to the occipital condyles
and nasion.
Bo

46. FACIAL AXIS
It is point from Ptm point to cephalometric
gnathion.

47. ESTHETIC PLANE/E PLANE
Is a line between the most anterior point
of the soft tissue nose and the soft tissue
chin.

48. THANK YOU