User's Manual

Document MV0319P.N
© Xsens Technologies B.V.
MVN User Manual
114
19.7 Segment axes definitions and Origin Definitions
Note: To ease comparison between the MVN segment co-ordinate systems with the International
Society of Biomechanics recommendation, currently based on optical position tracking systems, the ISB
recommendation is presented next to the MVN definition.
The MVN segment axes definition and origins have been chosen as closely as possible to the ISB
recommendation where whenever possible.
MVN
ISB
[
ii
]
O
Midpoint between right and left hip
center of rotation
Coincident with hip center of rotation
X
Perpendicular to Y and Z
Pointing forward
Line parallel to a line lying in the
plane defined by two ASISs and
midpoint of two PSIS, orthogonal to
Z-axis.
Pointing anteriorly.
Y
hipOrigin to jL5S1
Pointing up
Line perp. to X and Z.
Pointing cranially. (Della Croce et
al.
[iv]
)
Z
to jLeftHip to jRightHip
Pointing right
Line parallel to a line connecting
right and left ASISs.
Pointing right.
NB: Della Croce et al.
[iv]
define O as the midpoint between RASIS and LASIS
19.7.1 Spinal segments: L5, L3, T12, T8: Segments 2-5
MVN
ISB
[
ii
]
O
jL5S1, jL4L3, jL1T12, jT9T8
X
Pointing forward
Line per. Y and Z
Y
Joint to Joint
Pointing up
Line passing thru centers of
vertebra’s upper and lower
endplates
Z
Perp. to X and Y
Pointing right
Line parallel to a line joining
similar landmarks on the
bases and right and left
pedicles
Note: Spine segments not measured directly in MVN, they are interpolated between the MT’s of the
Pelvis, Sternum and Head using a model of the spine. Joint origins are the rotation points in the
vertebrae.