ISO 16840-1:2006
(Main)Wheelchair seating — Part 1: Vocabulary, reference axis convention and measures for body segments, posture and postural support surfaces
Wheelchair seating — Part 1: Vocabulary, reference axis convention and measures for body segments, posture and postural support surfaces
ISO 16840-1:2006 applies to seating intended to provide postural support within a wheelchair. It specifies: a global coordinate system that permits the determination and recording of a person's posture while seated in a wheelchair; the standard terms and definitions for use in describing both the posture and the anthropometrics of a person seated in a wheelchair; the terms and definitions for describing the dimensions, location and orientation of seating support surfaces, which together comprise the body support system. ISO 16840-1:2006 does not specify any methods for use in measuring a person's seated posture, nor does it define terms for dynamic physiological movements (such as flexion or extension). ISO 16840-1:2006 might be applicable to seating other than that intended to be used within a wheelchair.
Sièges de fauteuils roulants — Partie 1: Vocabulaire, convention des axes de référence et mesures des segments corporels, des surfaces de posture et du siège
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INTERNATIONAL ISO
STANDARD 16840-1
First edition
2006-03-15
Wheelchair seating —
Part 1:
Vocabulary, reference axis convention
and measures for body segments,
posture and postural support surfaces
Sièges de fauteuils roulants —
Partie 1: Vocabulaire, convention des axes de référence et mesures
des segments corporels, des surfaces de posture et du siège
Reference number
©
ISO 2006
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO 2006
The reproduction of the terms and definitions contained in this International Standard is permitted in teaching manuals, instruction
booklets, technical publications and journals for strictly educational or implementation purposes. The conditions for such reproduction are:
that no modifications are made to the terms and definitions; that such reproduction is not permitted for dictionaries or similar publications
offered for sale; and that this International Standard is referenced as the source document.
With the sole exceptions noted above, no other part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2006 – All rights reserved
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 General terms and definitions . 1
3 Abbreviated terms and subscripts. 6
3.1 Abbreviated terms . 6
3.2 Subscripts . 6
4 Global coordinate system principles. 7
4.1 General. 7
4.2 Structure . 7
5 Terms and definitions of an integrated geometric reference system . 7
5.1 General. 7
5.2 Global coordinate system. 8
5.3 Wheelchair axis system (WAS) . 9
5.4 Support surface axis system (SSAS). 10
5.5 Seated anatomical axis system (SAAS) . 11
6 Terms and definitions of support surface measures. 12
6.1 General. 12
6.2 Terms and definitions of support surface measures in the sagittal view. 13
6.3 Terms and definitions of support surface measures in the frontal view. 20
6.4 Terms and definitions of support surface measures in the transverse view. 26
7 Terms and definitions of body measures of a seated person . 30
7.1 General. 30
7.2 Terms and definitions of body measures in the sagittal plane. 31
7.3 Terms and definitions of body measures in the frontal view. 41
7.4 Terms and definitions of body measures in the transverse plane . 50
Annex A (normative) Definition of reference lines for common seating support surfaces . 56
Annex B (normative) Calculations of joint centres. 63
Annex C (informative) Abdominal and sternal body segment lines for use in sagittal and frontal
body measures. 68
Bibliography . 74
Alphabetical index . 75
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 16840-1 was prepared by Technical Committee ISO/TC 173, Assistive products for persons with disability,
Subcommittee SC 1, Wheelchairs.
ISO 16840 consists of the following parts, under the general title Wheelchair seating:
Part 1: Vocabulary, reference axis convention and measures for body segments, posture and postural
support surfaces
Part 2: Determination of physical and mechanical characteristics of devices intended to manage tissue
integrity — Seat cushions
Part 3: Determination of static, impact and repetitive load strengths for postural support devices
The following parts are under preparation:
Part 4: Seating systems for use in motor vehicles
Part 5: Determination of pressure relief characteristics of seat cushions intended to manage tissue
integrity
iv © ISO 2006 – All rights reserved
Introduction
The development of wheelchair seating as a sub-specialty of rehabilitation services has been occurring over
the last several decades. This practice involves the selection and provision of wheelchair seating products that
provide improved body support, movement control, and injury prevention for the wheelchair user. Inherent in
this selection process is the measurement and communication of the anthropometrics and postural measures
of the seated person, as well as the orientation, location and linear measures of the person's seating support
surfaces.
However, there has been tremendous variation in the use of the terminology and definitions related to the
clinical measures of a seated individual. Standard definitions and terms are lacking for communicating critical
postural information and support surface parameters in a way that is uniformly useful to service providers,
researchers, manufacturers, wheelchair users and purchasers when selecting and providing wheelchair
seating devices.
The purpose of this part of 16840 is to specify standardised geometric terms and definitions for describing and
quantifying a person’s anthropometric measures and seated posture, as well as the spatial orientation and
dimensions of a person’s seating support surfaces. This also allows for the systematic monitoring of a
person's seated posture change over time.
INTERNATIONAL STANDARD ISO 16840-1:2006(E)
Wheelchair seating —
Part 1:
Vocabulary, reference axis convention and measures for body
segments, posture and postural support surfaces
1 Scope
This part of ISO 16840 applies to seating intended to provide postural support within a wheelchair. It specifies:
a) a global coordinate system that permits the determination and recording of a person's posture while
seated in a wheelchair;
b) the standard terms and definitions for use in describing both the posture and the anthropometrics of a
person seated in a wheelchair;
c) the terms and definitions for describing the dimensions, location and orientation of seating support
surfaces, which together comprise the body support system.
This part of ISO 16840 does not specify any methods for use in measuring a person's seated posture, nor
does it define terms for dynamic physiological movements (such as flexion or extension).
This part of 16840 might be applicable to seating other than that intended to be used within a wheelchair.
2 General terms and definitions
2.1
absolute angle
angle which represents the orientation in space of a body segment or support surface reference plane relative
to the gravitational axis system
NOTE See 5.2.
2.2
body centreline
vertical line falling on the midsagittal plane of the body, as viewed in the frontal plane
2.3
body segment line
line defined by two designated body landmarks, either palpated or calculated, used in determining angular
positions of body segments
2.4
contact surface
surface of the seating support in contact with the seated person's body
2.5
depth
linear dimension of a seating support surface measured in the Y direction on a line parallel to the support
surface reference plane
See Figure 1.
Figure 1 — Examples of depth
2.6
length
linear dimension of a seating support surface measured in the Z direction on a line parallel to the support
surface reference plane
See Figure 2.
Figure 2 — Examples of length
2.7
reference position
fixed hypothetical baseline position to which other positions may be referenced
2.8
relative angle
angle formed between two body segment lines or two support surface reference lines
2 © ISO 2006 – All rights reserved
2.9
seated anatomical axis system
SAAS
axis system used to define the orientation of the body segments in space and to each other
2.10
seated reference position
SRP
orthogonal seated position to which other positions may be referenced
2.11
support surface axis system
SSAS
axis system used to define the orientation, location and linear dimensions of seating support surfaces
2.12
support surface geometric centre
SSGC
point of intersection of two or more lines joining the furthest points from the edges of a contact surface,
measured along the surface
See Figure 3.
a) Asymmetric contoured surface b) Planar surface
Key
1 line along the contoured surface
2 support surface geometric centre (SSGC)
Figure 3 — Illustration of the SSGC on curved and planar support surfaces
2.13
support surface reference line
designated line passing through the support surface geometric centre used in measurement of the absolute
and relative angles of the seating support surface
2.14
support surface reference position
SSRP
fixed hypothetical baseline position of support surfaces in the three orthogonal planes to which other positions
may be referenced
2.15
support surface reference plane
plane passing through the SSGC tangential to the surface curvature at the SSGC radius at the point of the
SSGC
See Figure 4.
NOTE The tangent to the radius of a planar surface is parallel to the surface.
a) Symmetrical contoured b) Asymmetrical contoured c) Planar surface
support surface support surfaces
Key
1 support surface referen
...
INTERNATIONAL ISO
STANDARD 16840-1
First edition
2006-03-15
Wheelchair seating —
Part 1:
Vocabulary, reference axis convention
and measures for body segments,
posture and postural support surfaces
Sièges de fauteuils roulants —
Partie 1: Vocabulaire, convention des axes de référence et mesures
des segments corporels, des surfaces de posture et du siège
Reference number
©
ISO 2006
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO 2006
The reproduction of the terms and definitions contained in this International Standard is permitted in teaching manuals, instruction
booklets, technical publications and journals for strictly educational or implementation purposes. The conditions for such reproduction are:
that no modifications are made to the terms and definitions; that such reproduction is not permitted for dictionaries or similar publications
offered for sale; and that this International Standard is referenced as the source document.
With the sole exceptions noted above, no other part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2006 – All rights reserved
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 General terms and definitions . 1
3 Abbreviated terms and subscripts. 6
3.1 Abbreviated terms . 6
3.2 Subscripts . 6
4 Global coordinate system principles. 7
4.1 General. 7
4.2 Structure . 7
5 Terms and definitions of an integrated geometric reference system . 7
5.1 General. 7
5.2 Global coordinate system. 8
5.3 Wheelchair axis system (WAS) . 9
5.4 Support surface axis system (SSAS). 10
5.5 Seated anatomical axis system (SAAS) . 11
6 Terms and definitions of support surface measures. 12
6.1 General. 12
6.2 Terms and definitions of support surface measures in the sagittal view. 13
6.3 Terms and definitions of support surface measures in the frontal view. 20
6.4 Terms and definitions of support surface measures in the transverse view. 26
7 Terms and definitions of body measures of a seated person . 30
7.1 General. 30
7.2 Terms and definitions of body measures in the sagittal plane. 31
7.3 Terms and definitions of body measures in the frontal view. 41
7.4 Terms and definitions of body measures in the transverse plane . 50
Annex A (normative) Definition of reference lines for common seating support surfaces . 56
Annex B (normative) Calculations of joint centres. 63
Annex C (informative) Abdominal and sternal body segment lines for use in sagittal and frontal
body measures. 68
Bibliography . 74
Alphabetical index . 75
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 16840-1 was prepared by Technical Committee ISO/TC 173, Assistive products for persons with disability,
Subcommittee SC 1, Wheelchairs.
ISO 16840 consists of the following parts, under the general title Wheelchair seating:
Part 1: Vocabulary, reference axis convention and measures for body segments, posture and postural
support surfaces
Part 2: Determination of physical and mechanical characteristics of devices intended to manage tissue
integrity — Seat cushions
Part 3: Determination of static, impact and repetitive load strengths for postural support devices
The following parts are under preparation:
Part 4: Seating systems for use in motor vehicles
Part 5: Determination of pressure relief characteristics of seat cushions intended to manage tissue
integrity
iv © ISO 2006 – All rights reserved
Introduction
The development of wheelchair seating as a sub-specialty of rehabilitation services has been occurring over
the last several decades. This practice involves the selection and provision of wheelchair seating products that
provide improved body support, movement control, and injury prevention for the wheelchair user. Inherent in
this selection process is the measurement and communication of the anthropometrics and postural measures
of the seated person, as well as the orientation, location and linear measures of the person's seating support
surfaces.
However, there has been tremendous variation in the use of the terminology and definitions related to the
clinical measures of a seated individual. Standard definitions and terms are lacking for communicating critical
postural information and support surface parameters in a way that is uniformly useful to service providers,
researchers, manufacturers, wheelchair users and purchasers when selecting and providing wheelchair
seating devices.
The purpose of this part of 16840 is to specify standardised geometric terms and definitions for describing and
quantifying a person’s anthropometric measures and seated posture, as well as the spatial orientation and
dimensions of a person’s seating support surfaces. This also allows for the systematic monitoring of a
person's seated posture change over time.
INTERNATIONAL STANDARD ISO 16840-1:2006(E)
Wheelchair seating —
Part 1:
Vocabulary, reference axis convention and measures for body
segments, posture and postural support surfaces
1 Scope
This part of ISO 16840 applies to seating intended to provide postural support within a wheelchair. It specifies:
a) a global coordinate system that permits the determination and recording of a person's posture while
seated in a wheelchair;
b) the standard terms and definitions for use in describing both the posture and the anthropometrics of a
person seated in a wheelchair;
c) the terms and definitions for describing the dimensions, location and orientation of seating support
surfaces, which together comprise the body support system.
This part of ISO 16840 does not specify any methods for use in measuring a person's seated posture, nor
does it define terms for dynamic physiological movements (such as flexion or extension).
This part of 16840 might be applicable to seating other than that intended to be used within a wheelchair.
2 General terms and definitions
2.1
absolute angle
angle which represents the orientation in space of a body segment or support surface reference plane relative
to the gravitational axis system
NOTE See 5.2.
2.2
body centreline
vertical line falling on the midsagittal plane of the body, as viewed in the frontal plane
2.3
body segment line
line defined by two designated body landmarks, either palpated or calculated, used in determining angular
positions of body segments
2.4
contact surface
surface of the seating support in contact with the seated person's body
2.5
depth
linear dimension of a seating support surface measured in the Y direction on a line parallel to the support
surface reference plane
See Figure 1.
Figure 1 — Examples of depth
2.6
length
linear dimension of a seating support surface measured in the Z direction on a line parallel to the support
surface reference plane
See Figure 2.
Figure 2 — Examples of length
2.7
reference position
fixed hypothetical baseline position to which other positions may be referenced
2.8
relative angle
angle formed between two body segment lines or two support surface reference lines
2 © ISO 2006 – All rights reserved
2.9
seated anatomical axis system
SAAS
axis system used to define the orientation of the body segments in space and to each other
2.10
seated reference position
SRP
orthogonal seated position to which other positions may be referenced
2.11
support surface axis system
SSAS
axis system used to define the orientation, location and linear dimensions of seating support surfaces
2.12
support surface geometric centre
SSGC
point of intersection of two or more lines joining the furthest points from the edges of a contact surface,
measured along the surface
See Figure 3.
a) Asymmetric contoured surface b) Planar surface
Key
1 line along the contoured surface
2 support surface geometric centre (SSGC)
Figure 3 — Illustration of the SSGC on curved and planar support surfaces
2.13
support surface reference line
designated line passing through the support surface geometric centre used in measurement of the absolute
and relative angles of the seating support surface
2.14
support surface reference position
SSRP
fixed hypothetical baseline position of support surfaces in the three orthogonal planes to which other positions
may be referenced
2.15
support surface reference plane
plane passing through the SSGC tangential to the surface curvature at the SSGC radius at the point of the
SSGC
See Figure 4.
NOTE The tangent to the radius of a planar surface is parallel to the surface.
a) Symmetrical contoured b) Asymmetrical contoured c) Planar surface
support surface support surfaces
Key
1 support surface referen
...
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