Introduction:

In order to study man particularly that of the skeletal

remains of the skull and the face, certain specialised

instruments such as Tubular Craniophore, Cubic Craniophore

and Diagraph etc. have been designed for the purpose. This

particular aspect is dealt under Craniometry, one of the

divisions of anthropometry.

Craniometry is concerned with the

technique of measurements on the

skull and face of the skeleton. It

includes measurements of different

types such as linear, angular,

depth, volume, arc, etc., and hence different types of

instruments are needed to take

different types of measurements.

Some measurements are taken

directly on the skull which is

commonly known as direct

measurements, while others are

measured on the craniograph of the skull which is commonly

known as indirect measurements. Direct measurements are

taken by placing the skull on a pad or by mounting it on a

craniophore. In case of indirect measurement tracing is done

with the help of a set of instruments

designed for the purpose.

When compared to the

landmarks used in somatometry the

cranial landmarks are well-defined

and are much easier to locate. As in

somatometry, in craniometry also it is

always necessary to have a full knowledge

about the landmarks, to locate them

accurately, and then to take the measurements correctly

following the standard techniques.

In order to take measurements, more particularly angular

measurements, the skull must be oriented on a fixed plane

which must be well defined and accepted by all workers.

Otherwise, with the variation of the plane, the measurements

will vary and hence it will not be comparable. With regard to

the planes of orientation, Juan Comas has highlighted that

one of the problems of visual comparability of the skull can be

solved in one way only and that is by making type drawing

and then comparing them directly by either placing them side

by side, or by super imposing one type drawing upon another.

Although many planes have been suggested and Krogman

has gone to the extent of describing up to 20 yet one of the

most well defined planes and is internationally accepted is

that of the Frankfurt Horizonal Plane or eye-ear plane. The

F.H.P. is based on placing the right and left porion and the

two orbitales in the same horizontal plane. It is used as a

constant plane of reference by the physical anthropologist

when he is measuring and describing skulls.

Another plane known as nasion-inion plane is used to take

a few angular measurements. When the nasion and inion are

on the same horizontal plane, it is called nasion-inion plane.

When dealing with incomplete skulls which lack one of

these points, measurements are oriented by the nasion-inion,

glabella-inion, and even occasionally the

glabella-lambda planes or lines.

A skull may be observed from

different norms or positions. They are

1.The cranium viewed from

above(norma verticalis)

2. The cranium viewed from

below(norma basalis)

3.The cranium viewed from side right

or left (norma

lateralis)

4. The cranium viewed from front

(norma frontalis)

5. The cranium viewed from behind

(norma occipitalis).

In fact, Blumenbach (1752-1840), the founder of

craniometry has classified mankind into three different types

on the basis of the form of the skull as seen from above

(norma verticalis). The three types are the Mongolians

showing square shape, the Negroes having long and laterally

compressed shape and the Caucasians with a shape

intermediate between the former two. Hence, it is from the

skull that racial identification too can be established.

A craniographic technique involves the drawing of curves

in different planes of the skull. The best curve systems are

those of Sarasin, which are based on correct orientation of

skulls and are useful in the reconstruction of skulls. It consists

of

1. Three sagittal curves

2. Three frontal curves and

3. Four horizontal curves

Identification of the

Instruments

1. Tubular Craniophore:

It consists of a long hollow metal tube which slides in and

out of another tube fixed on a heavy tripod base provided

with adjustable screws. Here, the purpose of having a long

hollow tube whereby it can slide up & down or in and out of

another metal tube is meant for adjusting the height of the

Tubular Craniophore as per the requirement. So also the

screws provided at the tripod base is meant for adjustment to

a required level. The top of the inner tube bears an

adjustable jaw-like structure i.e. the skull holder, to which the

skull is fitted at the foramen magnum. The jaws can be

moved in two directions i.e. forward and backwards as well as

from side to side.

Manipulation:

The instrument is first placed

on a leveled plane. The skull is

then mounted at the foramen

magnum on the adjustable jaw-like structure otherwise

known as the skull holder. With the help of horizontal needle

of Martin, the skull so mounted is placed in the Frankfurt

Horizontal Plane. The height of the

tubular craniophore can be conveniently

adjusted using the screw provided at the

side. Further, adjustments can be done

with the help of the adjustable screws

provided at the tripod base. Assuming

that all the required points are in the

same plane, the required angular readings are recorded using

sliding caliper to which the attachable Goniometer is fitted to

it.

Precaution:

To avoid any damage to the

skull while fitting or mounting it

to the skull holder, cotton pads

are used as a precautionary measure. The skull should be

properly oriented on the fixed Frankfurt Horizontal Plane less,

the variation of the plane will lead to inaccurate reading.

Utility:

It is used for orienting the

skull in a desirable plane with the

help of Martin’s Horizontal needle

for taking direct angular

measurements such as Metopic

Angle, Nasal Profile Angle, Facial Profile Angle etc.

2. Cubic craniophore:

As the name implies the

instrument is cubical in shape. It

consists of a metallic skeleton

cube form by 12 metal bars with

side length of 30 cm

approximately. A jaw-like

structure for holding the skull is

fixed in the centre of the cube by means of an extended arm

on one side of the height. To the jaw-like structure, the skull

to be measured or the drawings to be done is fitted at its

foramen magnum and thus the skull remains within the cube.

Manipulation:

The skull which is to be

craniographed/drawn or to be

measured is mounted on the

clamp using cotton pads. The

cotton pads so used should be

placed in such a way that the

basion point remain uncovered

so as to be able to locate while drawing the contour of the

skull. Proper adjustment is made with the help of the

adjustable screws. With the help of the sliding caliper the

skull so mounted is placed in the N.I. plane i.e. the nasion &

inion points are at an equal distance from the left side of the

metal bar. This should not disturb the Frankfurt Horizontal

Plane. The skull has to be kept on the Frankfurt Horizontal

Plane using Martin’s Horizontal

needle. Then Sarasin’s curve

system i.e. (nasion-basion

sagittal curve) is employed for

drawing the contour of the skull.

The craniophore is turned in such

a way that the skull is placed in

a norma lateralis position. The cubic craniophore is then

placed on the drawing sheet/paper & the outline of the four

arms of the cubic craniophore drawn with the help of a pencil

as close to the frame as possible. If the craniophore has been

moved the outline so drawn will enable to bring back the

craniophore to its original position.

Precaution:

The skull has to be mounted on the Frankfurt Horizontal

Plane without which the craniographic drawings including the

angle readings will not be accurate. Cotton pads have to be

adequately used to avoid any damage to the skull while

orienting it to the skull holder.

Utility:

The cubic craniophore is used at

the time of making sectional

drawing of a skull. It is used for

drawing craniograms by means of

diagraph as well as for drawing the

normas under dioptrographs or

taking their photographs. The contour so drawn can be used

for taking indirect angular measurements.

3. Diagraph:

It consists of a vertical bar bearing

two horizontal needles. The upper one

is curved and pointed. The height of

the upper curved needle can be

adjusted to the required level using

the screws provided at the vertical bar.

It can also be rotated in any direction

for convenience while drawing the craniograph. The lower one

carries a pencil holder exactly vertical in line with the point of

the curved needle.

Manipulation:

For making the sectional drawing of a skull provided it

requires not only a number of steps/procedure to be followed

but it also required other instruments such as Cubic

Craniophore, Martin’s Horizontal Needle as well along with the

Diagraph. For this the skull to be craniographed is first

mounted on the clamp of the cubic craniophore. With the help

of Martin’s Horizontal needle it is kept on the Frankfurt

Horizontal Plane. Then nasion-basion sagittal curve of

Sarasin’s Curve Systems is employed for drawing the

contours of the skull. As mentioned earlier the skull is placed

in a norma lateralis position. The cubic craniophore is then

placed on the drawing sheet/paper & the outline of the four

arms of the cubic craniophore

drawn with a pencil as close to the

frame as possible. The outline so

drawn will help in placing it back

in its original position if any

disturbance has taken placed on

the Cubic Craniophore.

The arrangement of the

diagraph is such that the tip of the

curved arm and the tip of the

pencil remain exactly in the same

vertical line. Having all set in this

position the diagraph is then

placed at right angle for drawing

the contour of the skull. When the upper arm is moved just

touching the skull the pencil makes a drawing of the same on

the paper attached to the wall of the cube that rests on the

table.

While drawing the contour of the skull, the lead should be

kept sharp enough so that it makes a clear impression on the

paper. On the important landmarks a slight pressure is

applied on the pencil tip or using another pencil it should be

marked with a cross on the curve so as to make easily

identifiable when the lines are to be join between two

important landmarks.

Precaution:

The instrument has to be first checked for any

instrumental error i.e. the pointed tip of the diagraph should

be in the same vertical line. While drawing the contours of the

skull care has to be taken that the

upper pointed tip should not exert

any pressure on the skull less it not

only leave any unwanted impression

on the skull but it also distort the

sectional drawing as well. It should

also as far as possible remain at right angle to the skull cap.

In case of apertures, the pencil should be kept higher so that

it should not spoil the paper by smudging the drawing.

Utility:

The diagraph instrument is used for drawing the contours

of the skull which is properly adjusted in Frankfurt Horizontal

Plane on the Cubic Craniophore. The contour so drawn is

utilised for taking indirect angular measurements.

Conclusion:

The instruments so designed have been meaningfully

employed to take both direct and indirect measurements.

From the recorded measurements various indices have been

worked out whereby a number of conclusions have been

drawn. From the shape and sizes of the skull a close

phylogenic relationship between man and other primates can

be established. It is through the study of Craniometry

particularly that of tracing the contour of the various skulls a

lot of information can be obtained i.e. man’s position in the

animal kingdom can be ascertained. The shape and size of the

skull of man and his near relatives, the primates- both living

and extinct- can also be obtained by Craniometry.

The correlations among the different parts of the skull can

be established through Craniometry; as such the missing

portions of a skull can be reconstructed. Moreover, a skull can

be reconstructed from the available measurements of the

skull even if it is destroyed or lost.