DESCRIPTION OF SPECIFIC STUDIES IN MORPHOLOGICAL BIOMETRY The characteristics of the human body studies in morphological

GROUP SUBTESTS MEAN Z-SCORES STANDARDS MEAN Z-SCORES

2. DESCRIPTION OF SPECIFIC STUDIES IN MORPHOLOGICAL BIOMETRY The characteristics of the human body studies in morphological

biometry are essentially associated with two basic characteristics:

dimensions and masses.

72 G. IGNAZI ET AL.

These have long been a matter of concern, and a goal of study in physical anthropology since the measurement of the variability of human body dimensions was one of the "tools" used to classify and to compare various human groups. In recent decades, the rela- tively simple idea of measuring dfQensions has been changed, and many other characteristics (such as masses, mobility, strength) have been incorporated to fulfill the needs of other disciplines, such as physiology, biomechanics, ergonomy, and human engineering.

These sciences need information about characteristics of the human body as it varies intra- and interindividually, and under static and dynamic conditions. In contrast to the much simpler static case, in dynamic conditions physical characteristics change, often quickly, in time. Displacement and its time derivatives, speed and particularly acceleration, affect body characteristics under

dynamic circumstances.

As Fig. 1 indicates, basic human body dimensions can be defined in terms of height, length, width, and depth. A combination of these dimensions leads to such characteristics as body surface and body volume.

A second group of intrinsic characteristics is derived from the assessment of body masses.

A combination of these two main groups of intrinsic data may be considered "elementary" as they define more complex characteristics, such as inertial properties and densities. Inertial properties, in turn, can be defined in terms of the position of the over- all center of gravity, or the location of the centers of gravity of body segments; or with respect to the moments of inertia Ix, I y ' I z with respect to axes passing through one or several centers of

inertia (Fig. 2). Densities, either of the whole body or of its segments, are defined as the amount of mass per volume.

F THE HUMAN BODY

~

^TIME BIOLOGICAL RYTHMS ^LENGTH^{OF TIME} SPEEDS

ETC ....

DENSITIES

INERTIAL PROPERTI ES

MOMENTS INERTIA OF

Figure 1. Variable data measured in biometry.

DEVELOPMENT GROWTH SENESCENCE

PROGRESS AND PROSPECTS IN HUMAN BIOMETRY 73

x· ---H .,~-H---"i-+-·

.,

Figure 2. Principal axes of inertia in the human body.

The location of the segmentary elements is dependent on body posture, which hence must be considered both in static and dynamic biometry. If one introduces the factor time, the dynamic behavior of the human body is under study. Depending on the time scale, dynamic behavior may range from short-term studies of gesture and motion to long-term studies of the development, growth, and aging of the body.

3 • METHODS OF STUDY DEVELOPED IN THE LABORATORY

Method of measurement and of data processing have been developed for each group of biometrical characteristics defined above (Fig. 3).

DIMENSIONS I

I

~K

TRADITIONAL

-l

LINEAR MEASUREMENT:

ANTHROPOMETRY WITHOUT REFERENCE TO A TRIDIMENSIONAL SPACE

BIOSTEREOMETRY

--l

STEREOMETRIC MEASUREMENTWITH REFERENCE TO A

1

TRIDIMENSIONAL SPACE

MASSES I r ^WEIGHTING '--____ ..Jr---1.. FORCES PLATFORMS

FORCES PLATFORMS

ANTHROPOSTEREOMETRY PHOTOGRAMMETRY : STEREORESTI TUT! ON OPTO-ELECTRON I CAL TECHN IC : LASER

PENDULUM - - {LOCATION OF THE CENTRE OF MASS VALUE OF MOMENT OF INERTIA

~ TRADITIONAL METHOD DENSITIES

'--_ _ _ _ -' BIODENSITOMETRY

Figure 3. Laboratory studies and measurement methods.

74 G. IGNAZI ET AL, They include:

- dimensions,

- masses and forces, - inertial properties.

3.1. Measurement of Human Body Dimensions

Methods of measurement of the human body evolved as provoked by the distinct concerns of physical anthropology, and by the needs of other sciences, such as anatomy, biomechanics, physiology, and ergonomics. One main feature of this evolution is the need of defining dimensions according to. references in three-dimensional space.

3.1.1. Traditional anthropometry provides a more or less exhaustive collection of linear dimensions, i.e., direct measurement

".

II.

..r· ..•.

Figure 4. Measurements permitting the definition of the geometry of the seated or standing subject.

PROGRESS AND PROSPECTS IN HUMAN BIOMETRY 75

z

Figure S. Identification and localization of anatomical points in space, determining the segmentary length.

of distances between anatomical points, or bet'V'een points and reference surfaces (floor, wall) or perimeters or angles.

From these data, the geometry and composition of the human body can be restored by combining heights, lengths, widths, thicknesses, angles, and perimeters (Fig. 4).

3.1.2. Biostereometrl- stands out as a very significant step in the measurement of the human body. It not only gives values of the distances between anatomical points, as does classical anthropometry, but it also describes, with the greatest precision, the spa- tial location of segmentary elements of the human body with respect to a trirectangular reference system.

Each anatomical point which should ,be taken into account is identified by its coordinates X,Y,Z (Fig. 5). Thus, with the help of analytical geometry, one can calculate distances from point to point, from point to segment, from point to plane, distances between planes, angles of segments or planes, etc.

From these very general principles of biostereometry, we shall consider here only three technical soluticns:

- direct biostereometry with an anthropostereometer,

- photographic biostereometry with photograrnrnetry or orthogonal systems of photography,

- biostereometry with opto-electronic equipment: laser telemetry and optical sensor.

76 G. IGNAZI ET AL.

N = NASION

EN = ENDOCANTHION EC= ECTOCANTHION FT"" FRONTO TEMPORAL

T= TRAGU

"_I~ RIGHT SIDE LEFT SIDE

DISTANCES

mm m IT " ^mini ^{m •••}

'u' ","

^m ^IT _" ^mini ^{ml ...}

N - EN 26.33 2 .75 10.87 15.81 33.811 NS 25.25 2 . 73 10 .82 111. 215 3192 EN _EC 27.82 2 .38 8.54 21 .18 33 ~1 Nl' 27.97 2 .15 7.67 21 98 33 .~0

N - E C 63 .1~ 3 .38 6 .37 ~5 .~9 80. 7~ NS 53.22 311 5 .85 4~ 88 60. 2~

N - FT 80.88 5.25 8 .63 48.81 7.1.62 NS 6\ 02 438 7 . 15 52 .U 72 .52 N _ T 122.03 5 . 2~ :'.30 106. 22 134.67 NS 122 .12 ~ . 8~ 3 .97 IOO . ~ 133.99

Figure 6. Anthropostereometer and example of results.

PROGRESS AND PROSPECTS IN HUMAN BIOMETRY

, I

~ .

. ^..

.1',."

"~,~

, .

\' -- ~

SnTE" or STH!OIlUUC "U$U .. "IMT

UII JVA~ 11'0 PDP 11/)4

soFt IIAU EVCL I D

APPU II

HI nOCALCULATOa

'O."ATIO~ 0' A~ ATLAS or IUCH uus

C. A. D.

COMPUTtI AID OES ICN

sCln 0' YUUALUATIOH

. . COlD

TlACINC TAILE

Figure 7. Use of three-dimensional data for research area description.

78 G. IGNAZI ET AL.

Direct biostereometry or anthropostereometry: Developed in the laboratory and still being improved, it allows an automatic assessment of coordinates. In this system (Fig. 6), X,Y,Z coordinates of anatomical points are simultaneously assessed by mean of rods in contact with a landmark. The reference space is determined by the apparatus itself.

Whatever the orientation and the functional position of the subject and the segmentary elements (head, face, arm, hand, lower limb, etc.), they are perfectly located during the experiment in space.

It is obvious that such a method becomes valuable for the design of equipment and for the simulation of an operator's post of activity or workplace. In this context, the elements of the person (anatomical points) and the elements of the system (commands) are calculated according to a common reference system (Fig. 7). In this technique, biostereometric data are directly measured with an electronic sensor and numerized in a microcomputer (Apple II).

Indirect biostereometry with photography: The acquisition of biostereometric data is no longer made directly from the object, but from photographic or cinematographic pictures of this object.

Photogrammetry is one technique which is. presently highly developed and which gives very precise information (Fig. 8).

Figure 8. Example of three-dimensional photogrammetric restitution (from Duncan, Foort, and Mair).

PROGRESS AND PROSPECTS IN HUMAN BIOMETRY

Telemetric evaluation of the point A dimension (Z dim,nsion).

O"G Sensor field 0"0 Fixed

O"A' Sensor measurement O"A Calculated

Optic camera

Laser emitter

Figure 9. Principle of body measurement with a telemetry laser.

Unfortunately it requires the use of complex data collecting and processing systems, which hinders its general acceptance in the field of biostereometry. For example, this technique for dynamic biometry requires facilities to "chop" a gesture by stroboscopic effects.

In the study of motions, the use of a cinematographic system with movie cameras in orthogonal planes makes it possible to draw the trajectory of anatomical points in space.

Biostereometry with opto-electronic techniques~ telemetry by laser and optical sensors: This method (Fig. 9) is a great improve- ment in the technique of biometric characteristics measurement

because it makes it possible to locate any point of an object in space by the location of the light spot of the laser beam on a matrix of diodes of the camera. The third coordinate, Z, which measures the distance between points on the object and the camera-

laser system, is obtained by telemetric measurement. The great advantage of this technique is that no human operator has to inter- vene: coordinates X,Y,Z of the object are automatically measured and processed by means of computer equipment.

80 G. IGNAZI ET AL.

DIFFERENT TECHNIQUES TYPE OF MEASUREMENT TI ME OF ACQU I S IT I ON

I - TRAD I TI ONAL ANTHROPOMETRY LINEAR MEASUREMENT 60 TO 120 MEASUREMENTS MANUAL HANDLI NG Wb THOUT BY SUBJECT PER HOUR REFERENCE TO A 3- SPACE.

- ANTHROPOSTEREOMETRY :

3 - D 100 TO 300 PO I NTS BY

I

~IDH REFERENCE TO A

• ·DI RECT MEASUREMENT ••••••

SUBJECT PER HOUR - SPACE.

MANUAL HANDL I NG

DETERMINATION OF VOLUMES OF ACTIVITY.

, AUTOMATI SED MEASUREMENT • 3 - D 100 TO 1000 PO I NTS BY AUTOMATICAL DATA PROCESSING.

SUBJECT PER HOUR

- PHOTOGRAMMETRY : " ... ^{3 - D} PHOTO~RAPHIES DETERMINATION OF SURFACES,

1 TO MN, BY SUBJECT VOLUMES

- OF POINTS, DATA PROCESSING THROUGH AN OPERATOR.

- OPTO-ELECTRON I CAL TECHN IQUES

• LASER ••• " •••• "." ••• ,. 3 - D 30000 POINTS IN 5 SEC. AUTOMATICAL DATA PROCESSING BY SUBJECT,

Figure 10. Evolution of measurement techniques in biometry.

Figure 10 summarizes the characteristics of the various measurement techniques.

3.1.3. Morphology and "time factor." The concept of studies in human morphology must be dynamic: anthropometric description of the body at a given moment does not take into account the variability of the living body.

Time and duration appear inseparable from morphology. During short duration we analyze moments and gestures, and ov~r long duration, we note growth, development, and biological rhythms.

In this last case, the use of measurement techniques of the human body in three-dimensional space considerably enriches our knowledge of dynamic aspects in growth.

With time we consider a new notion of movement and progressive structuration of anatomic elements in space. It makes it possible, for example, to assess quantitatively in children harmonious or pathologic frequency of postures in orthopedics.

3.2. Methods of Measurement of Masses and Forces

The measurement of masses and effects of accelerations on masses of the human body is performed with well-known methods in biometry and biomechanics.

PROGRESS AND PROSPECTS IN HUMAN BIOMETRY

Under static conditions, when the only acceleration on the human body is the pull of gravity, weight is measured.

In contrast, during motion "g" acceleration is not the only factor: either by its own action, or in response to external force fields or impulses, the human body reacts and generates forces.

These forces are different from the simple weight value

Weight;' Mog in the static condition. Measurement of dynamic forces can be performed with a force platform, which indicates the forces transmitted to the body in three directions (Fig. 12 and 13).

3.3. Biometric Measurement of Inertial Properties of the Human Body The compound pendulum is one of the most precise tools to deter- mine inertial properties of the human body in a static position.

It allows us to measure accurately the values of inertial moments I in relation to the X,Y,Z axes passing through the center of mass G of the human body, according to the elementary relation

=

2II

V

_mg.d^I. ⁽¹⁾

where T is the period of the pendulum, I the moment of inertia of the pendulum, mg the weight of the pendulum, and d the distance from

Figure 11. Biostereometry and measurement of segmentary element displacement in a three-dimensional space, over time.

82 G. IGNAZI ET AL.

05.

""'01

^deI'Yary

:NI .J " ./'

. . ..

\00 doN

Figure 12.

... J

SHOOT PUTTER 2

Relation between characteristic events of forces and typical postures.

PROGRESS AND PROSPECTS IN HUMAN BIOMETRY

, y ,

Figure 13. Force platform with six components.

G, the center of gravity, to the axis of oscillation. Usually, measurements of the inertial properties of th~ human body are done by the double oscillation method application of the Huygens theorem.

The location of the center of mass itself, given by the measurement of the oscillation period of the pendulum and the masses

(man + pendulum), is defined according to its location in a trirectangular reference system. Anatomical points are located in the same reference system (Figure 14).

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