Craniometry is the technique used to measure the dry skull after removing its soft parts using various craniometric points and landmarks as reference points. Standard craniometric measurements include maximum cranial length, breadth, bizygomatic breadth, basion-bregma height, and facial heights and breadths. Instruments used include spreading calipers, sliding calipers, and measuring tapes. Various indices can also be calculated from craniometric measurements to study relationships between measurements. Cephalometry is similarly used in dentistry to analyze tooth and jaw relationships and positions.

1. CRANIOMETRY

2. Craniometry:
It is the technique used to measure dry skull after removal of its soft parts.
•A landmark on the skull from which craniometric measurements can be taken are
craniometric points.
•A landmark may be defined as a
definite anatomical point or an indefinite point located by geometrical relations
which form the termini of the direct measurement.

3. Points:
• Unpaired:
Nasion, glabella, bregma, akanthion, lambda, orale, opisthocranion, basion,
staphylion.
• Binate:
Pteryon, porion, euryon, zygion, gonion, endomolare.

4. Unpaired:
•Nasion: The intersection of the nasofrontal suture with the midsagittal
plane. Nasion is the uppermost landmark for the measure of facial height.
•Glabella: The most forward projecting point in the midline of the forehead
at the level of the supra-orbital ridges and above the nasofrontal suture.
•Bregma: The intersection of the coronal and sagittal sutures in the midline.

5. •Lambda: The intersection of the sagittal and lambdoidal sutures in the
midline.
•Opisthocranion: The most posterior point on the skull not on the external
occipital protuberance. It is the posterior end point of maximum cranial
length measured from glabella. It is determined instrumentally.
•Basion: The midpoint of the anterior margin of the foramen magnum.

6. Binate:
•Porion: The uppermost lateral point in the margin of the external
auditory meatus. The right and left porion with the left orbitale define the
Frankfort Horizontal.
•Zygion: The most lateral point of the zygomatic arch. It is determined
instrumentally.

7. •Gonion: The midpoint of the angel of the mandible between body and ramus.
•Euryon: The two points on the opposite sides of the skull that form termini of the lines of
greatest breadth. The two points are determined instrumentally.
•Pterion: Estimated as 2 finger-breadths above the zygomatic arch and a thumb’s breadth
behind the frontal process of the zygomatic bone.

8. Orale
Endomolare
Staphylion
Basion

9. Glabella
Nasion
Akanthion
Gnathion
Bregma
Lambda
Opistocranion

10. Porion
Pteryon

11. Zygion
Euryon
Gonion

12. Length: Glabella - Opisthocranion
Width: Euryon - Euryon
High: Bregma - Basion
SIZE OF THE SKULL

13. Length: Nasion - Gnathion
Width: Zygion - Zygion
SIZE OF THE FACE

14. Width: Endomolara - Endomolare
Length: Orale - Staphylion
SIZE OF THE PALATUM

15. Skull is the upper most part of the human skeleton consisting of
head and face. The human skull consists of 22 bones. Except for the mandible
(lower jaw), all the bones of the skull are connected together by sutures. The
skeleton of a skull without mandible is called Cranium which is made up of 8
bones and thirteen bones form the facial skeleton. The mandible is a movable
bone held to the cranium by ligaments. The cranial bones can be divided into
two categories: the calvaria and the cranial base. The calvaria is the
domeshaped superior portion of the cranium. It is composed of the frontal,
occipital, and parietal bones, and the flat portion of the temporal bones. The
cranial base is composed of the two remaining cranial bones, the ethmoid and
the sphenoid bone. Fourteen facial bones form the other components of the
skull. The facial bones are composed of the inferior nasal conchae, lacrimal
bones, mandible, maxillary bones, nasal bones, palatine bones, vomer and
zygomatic bones.
SKULL

17. INSTRUMENTS USED FOR
CRANIOMETRY
Instruments like spreading caliper, sliding caliper, steel tape and mandibulometer
are used while recording craniometric measurements.
•Calipers
Calipers are the most important instruments available for measuring distances
between two definite points. There are two types of calipers-Spreading and
Sliding.

18. •Spreading Caliper
This instrument is available in two sizes i.e. 25 cm long for taking smaller
measurements and another one 60 cm long for taking the measurements on
Pelvis and hence it is called as Pelvimeter. The caliper comprises of two long
arms which are curved outwards and bounded at one end. A meter scale is
fixed to one of the arms and passes through the socket on the second arm.
The spreading calipers are made with blunt or rounded ends and sharp or
pointed ends. The spreading caliper with rounded or blunted ends is used to
make measurements on living human being, whereas, the spreading caliper
with sharp or pointed end is employed to record measurements on skeletons.
The calipers are graduated up to one millimeter

19. Spreading Caliper

20. Sliding Caliper

21. CRANIOMETRIC MEASUREMENTS
The procedures for various craniometric measurements are presented as
below:
Maximum Cranial Length (g - op): It measures the straight distance
between glabella (g) and opisthocranion (op).
Instrument: Spreading Caliper (Pointed end)
Procedure: A skull is placed on the working table or on the seed bag. One
point of spreading caliper is kept on the glabella and other point is moved to
the posterior region of the skull on the occipital bone in midsagittal plane and
wherever the maximum length is observed it should be measured.

22. Recording of Cranial Length

23. Maximum Cranial Breadth (eu – eu): It is the maximum breadth
(width) measured on the skull on right angle (90º) to the mid-sagittal
plane.
Instrument: Spreading Caliper
Procedure: Place the skull on the working table or on the seed bag. Keep
the two points of the spreading caliper on two sides of the euryon with
the two hands in the same horizontal plane and record the measurement.

24. Recording of cranial breadth

25. Maximum Bizygomatic Breadth (zy – zy): It measures the straight
distance between two zygia (zy) which are the most laterally placed points
on the zygomatic bone.
Instrument: Spreading caliper
Procedure: A skull is placed on the table in norma verticalis position. Two
points of the spreading caliper are kept on zygion of either side of the skull,
wherever maximum breadth observed it should be recorded.

26. Basion-Bregma Height (ba – b ): It measures the straight distance
between basion (ba) and bregma (b).
Instrument: Spreading caliper
Procedure: The skull is placed in norma lateralis position while right side
rests on the pad. Basion and bregma landmarks are located on the skull.
One end of spreading caliper is kept on the basion on the backside of the
skull and the other end of the caliper is moved to the bregma of the skull
and the measurement is made.

27. Upper Facial Height (n – pr): It measures the straight distance between
nasion (n) to prosthion (pr).
Instrument: Sliding caliper
Procedure: The skull has to be placed in such a manner that the occipital
region rests on the pad. One point of sharp end of caliper is kept on nasion
and the movable point is extended to the prosthion and the measurement is
recorded.

28. Minimum Frontal Breadth (ft): It measures the straight distance between
frontotemporale located on either side of the skull.
Instrument: Sliding caliper
Procedure: A skull is placed on the working table. Frontotemporale on either
side of the skull are identified. One sharp end of the caliper is placed on the
frontotemporale on the one side of the skull and the movable point is spread
up to the frontotemporal end on the other side of skull and wherever the least
distance is observed the measurement should be made.

29. Morphological Facial Height (n – gn): It measures the straight distance
between nasion and gnathion.
Instrument: Sliding Caliper
Procedure: The measuring skull should be placed towards the measurer.
Nasion and gnathion landmarks are identified on the skull. The sharp end of
the caliper is kept on the nasion and the movable part of the caliper touches
the gnathion and the measurement is made.

30. Nasal Height (n – ns): It measures the straight distance between nasion and
nasospinale.
Instrument: Sliding Caliper
Procedure: The skull is kept in such a manner that the basal region rests on
the pad. The fixed point of cross-bar is placed on nasion (n) and the movable
crossbar is adjusted against the nasospinale (ns).

31. Nasal Breadth: It measures the maximum breadth of the pyriform aperture.
Instrument: Sliding Caliper
Procedure: The skull to be kept on the working table. The measurement
should be taken by Sliding Caliper by placing the two ends of the cross-bars
on the two farthest points of the nasal aperture.

32. Facial length or Facial depth (ba-pr): It measures the straight distance
between basion and prosthian.
Instrument: Sliding Caliper
Procedure: The skull is placed in the position of norma basalis on the working
table facing the measurer. Identify the prosthion and basion landmarks on the
skull. One sharp point of Sliding Caliper is kept on the prosthion and the
movable point is spread to the level of basion and the measurement is made.

33. Upper Facial height (n-pr): It measures the straight distance between nasion
and prosthion.
Instrument: Sliding Caliper
Procedure: The skull is placed on the working table in frontal part facing the
measurer. Nasion and Prosthion landmarks are identified. One sharp end of the
sliding caliper is kept on nasion and the movable point is drawn to the prosthion.

34. Horizontal Circumference of skull (g-op-g): It is the maximum
circumference of the cranium in horizontal plane over glabella (g) –
opisthocranion (op)- glabella (g).
Instrument: Measuring tape
Procedure: The skull is placed facing frontal region facing the measurer. The
landmark opisthocranion is located which is found on the back of the skull.
Passing the tape through opisthocranion the maximum circumference between
glabella to glabella is measured.

35. Morphological Facial height (n-gn): It measures the straight distance
between nasion and gnathion.
Instruments: Sliding Caliper
Procedure: The skull is placed on the working table facing frontal region to
the measurer. Identify and mark the nasion and gnathion landmarks. Keep one
sharp point of the Sliding Caliper on gnathion and draw the movable sharp
point towards nasion and record the measurement.

36. Breadth of the Upper Jaw or Bimaxillary Breadth (zm-zm): It measures
the straight distance between two zygomaxillaria.
Instruments: Sliding Caliper
Procedure: Place the skull on the working table facing the measurer. Identify
Zygomaxillare on either side of the skull. Keep one sharp fix point on left
zygomaxillare and draw the movable sharp point towards the right
zygomaxillrea and record the measurement.

37. INDICES
An Index represents the relationship between two absolute measurements.
Various indices can be calculated based on craniometric measurements.
However, some of the indices are given below.

38. CEPHALOMETRY
•It is used in dentristy, especially in orthodontics, to gauge the size and
special relationships of the teeth, jaws and cranium.
• This analysis informs treatment planning, quantifies changes during
treatment, and provides data for clinical research.

39. CEPHALOMETRIC POINT, PLANE, LINE AND ANGLES
USED IN DENTISTRY
S (Sella):
Midpoint of sella turcica
N (Nasion):
Most anterior point on fronto-nasal suture
Or (Orbitale):
Most inferior anterior point on margin of orbit
Po (Porion):
Upper most point on bony external auditory meatus
ANS (Anterior Nasal Spine)
PNS (Posterior Nasal Spine)

40. Go (Gonion):
Most posterior inferior point on angle of mandible
Me (Menton):
Lower most point on the mandibular symphysis
A (A point):
Position of deepest concavity on anterior profile of maxilla
B (B point):
Position of deepest concavity on anterior profile of mandibular symphysis

41. Frankfort Plane: Po – Or
Equivalent to the true horizontal when patient is standing upright
Maxillary Plane: PNS - ANS
Gives inclination of maxilla relative to other lines/planes
Mandibular Plane: Go - Me
Gives inclination of mandible relative to other lines/planes

42. Thank You