View Full Version : co-ordinate axes and rotations for 3-D

Barry Sidney Myers
06-16-1993, 09:29 PM
Dear readers,

My students and I study the biomechanics of cervical spine trauma. We
have just implemented an algorithm, based on Herman Woltring's
software, to calculate Euler angles using an xyz convention from
biplanar high speed video data.

This has raised the question of the orientation of the co-ordinate axes
relative to the spine, and the order of the rotations. There are
different practices used by the various groups (automotive, aerospace,
orthopaedic, etc.), and this has raised a number of questions as to the
best choice.

Is there a consensus opinion or standard on this subject?

Given that axial rotation and lateral bending are strongly coupled
rotations, while, flexion-extension rotation is relatively uncoupled,
is there a prefered order of coordinate rotations? Is the selection of
any real consequence in this particular problem?

Any thoughts would be greatly appreciated.


Barry Myers