View Full Version : Summary of Replies - Shoulder Joint Centre

unknown user
11-09-2000, 09:01 AM
The following is a list of replies to my question which was posted on Oct.26
regarding determination of the shoulder joint centre based on body segment
marker position data. Thanks to all for your help in this matter.

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Agnes Roby-Brami wrote:

We recently developped a method of 3D recording of human upperlimb
movement using electromagnetic Polhemus sensors and a 3 links rigid
bodies model (Biryukova et al). We obtained accurate measure of the
center of shoulder coordinates during pointing movements.
A polhemus sensor is fixed on the skin above the acromion, so it is also
possible to obtain position and orientation of the scapula. However, we
did not yet evaluated the errors due to the displacement of the skin
over acromion.

Biryukova E.V., Roby-Brami A., Frolov A.A., Mokhtari M. Kinematics of
human arm reconstructed from spatial tracking system recordings. J.
Biomech. 2000, 33 : 985-995.

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Kjartan Halvorsen wrote:

I guess you are familiar with the fact that the actual center of motion of
the shoulder joint, or any other joint of the human body for that matter,
moves around with respect to the anatomy. Thus there is not strictly a
single well defined point, call it the center of the shoulder joint complex,
which is in rest for all motions of the joint.

One might still want to simplify the situation by assuming a single point,
fixed with respect to the anatomy, as the center of the shoulder joint. As
I understand your question, this is what you are looking for.

Together with colleagues, I have been working on this problem. I invite you
to take a look at the paper

Halvorsen K, Lesser M, Lundberg A.
"A new method for estimating the axis of rotation and the center of
J Biomech. 1999 Nov;32(11):1221-7.

The ideas presented in this article are further developed in the licentiate

Halvorsen K
"Model-based methods for tracking and analysis of human movement." Licentiat
thesis, Dept of Systems and Control, Uppsala University, 1999

The easiest way to get the thesis is to download it from the web site
Alternatively, you may request a copy directly from the department. In this
case, please send the request to iw@syscon.uu.se

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"Amanda Fang Lin" wrote:

'The glenohumeral joint rotation centre in vivo', by M Stokdijk, et al.

'The position of the rotation center of the glenohumeral joint', by HEJ
Veeger. p1711-1715

Both on J. Biomechanics, 2000, issue 12 (December)

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Leonard Elbaum wrote:

Problematically, the humerus moves tranlationally as well as rotationally,
so there is no joint center! I'm sure others will give you the best, most
useful estimates.

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Cliff Fornwalt wrote:

My name is Cliff Fornwalt, and I'm working on upper extremity
modelling with optical motion capture systems. I am using the vicon
system at the University of Southern California to collect my data and I'm
writing a model using their BodyBuilder for biomechanics software. From
what I understand, there are very few biomechanics researchers out there
with the programming experience to write such a model, so, as far as I
know, I'm the only one doing this. I spent several months this summer
trying to locate the shoulder joint center, and I developed several
methods. None of these methods seemed to give satisfactory results. I
found an excellent method that uses magnetic motion capture systems
(Polhemus) to identify not only marker positions, but also marker refeence
frames. Using these reference frames, one can write a program in C++ or
some other programming environment that will estimate the shoulder joint
center from the relative rotations of markers (and their reference
frames) on the upper arm and on the acromion.

This method was developed by Elena Biryukova at the Russian
academy of sciences in Moscow. Her results are quite good (I'll give you
the publication reference at the bottom of this email) but her method uses
a magnetic motion tracking system. As you probably know, magnetic systems
cannot be used for any experiment where there is a substantial amount of
metal in the workspace. I believe this would preclude the use of force

Since the primary goal of our research here is kinematics, and
does not require high precision, I have abandoned for now the pursuit of
the shoulder joint center. My model currently just estimates the center
by adding a vector of a user-definable magnitude to the acromion marker in
the downward direction (aligned with the downward pointing axis of the
trunk as I define it). Of course, this does not account for scapular

However, I did spend a good bit of time trying to adapt Dr. Biryukova's
methods to optical tracking systems, and I do believe it is possible. It
requires that one have not only the location of a marker fixed in an
arbitrary position on the humerus segment, but also a reference frame. I
accomplished this by using a 3 marker tree with the markers at the ends of
10 mm sticks that point orthogonally out from an origin. This was kind of
bulky, and required calculation of the origin point, which more than doubled
my model running time. (To about 1.5 min
per 20 sec trial) This method could be improved by using a 4 marker tree
with an extra marker at the tree's origin.

The other problem that I have encountered (and that I consider to
be my only barrier to success in finding the shoulder joint rotation
center) is defining a rotation matrix from vicon's outputs. Vicon
provides very poor documentation on the methods they use to calculate
the Euler angles that BodyBuilder outputs, and I have been unable to
create a rotation matrix from these outputs. BodyBuilder has an
alternative to their Euler angle outputs, called Helical Vectors
(essentially quaternions or Euler parameters) which should allow me to
more easily and directly calculate a rotation matrix from the
outputs. However, Vicon provides NO documentation for this set of
outputs (makes you wonder why they have them if they don't tell anyone
what they mean). I have been waiting for the last month for the
support staff to get back to me with some form of documentation on this.

Once they do, I will complete my emulation of Dr. Biryukova's
method with an optical system as time permits.

This is the reference for Dr. Biryukova's shoulder joint center research.

E.V. Biryukova et al. Journal of Biomechanics 33 (2000) pp 985-995

Maury A. Nussbaum at the Virginia Polytechnic Institute and state
University is developing some very sophisticated methods for finding all
upper extremity joint centers. He sent me a copy of his manuscript that
he was submitting for publication as of 2 months ago. I don't know if it
has been published, but you can email him at nussbaum@vt.edu.

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"Antony Hodgson" wrote:

I'd suggest you get in touch with Anthony Choo, who's working at the
Orthopaedic Engineering lab at Vancouver Hospital

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dirkjan veeger wrote:

Veeger, H.E.J. (2000) The position of the rotation center of the
glenohumeral joint, Journal of Biomechanics, 33, 1711-1715.

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"Anthony Min Te Choo" wrote:

As far as I know, there is no standard or "proven" method of assessing
scapular motion other than with x-rays. It is still an unresolved probelem.

Some authors that come to mind are:
They all have published stuff on non-invasive techniques.

Other well referenced authors (pretty "old" papers) for scapular motion are:


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"Maury A. Nussbaum" wrote:

Nussbaum, M.A., Zhang, X. (2000) Heuristics for locating upper extremity
joint centers from a reduced set of surface markers, Human Movement Science,
September, 1-20.

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"Adrian Morphett" wrote:

Stokdijk, M., Nagels, J, Rozing, P.M. (2000) The glenohumeral joint
rotation centre in vivo, Journal of Biomechanics, 33, 1629-1636.

Also, the following paper has an easy method of finding the GH CoR along the

arms longitudinal axis:

de Leva P. Joint center longitudinal positions computed from a selected
subset of Chandler's data. Journal of Biomechanics. 1996;29(9):1231-1233

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Lorcan Coffey wrote:

O'Brien, J. F., Bodenheimer, B. E., Brostow, G. J., Hodgins, J. K.,
"Automatic Joint Parameter Estimation from Magnetic Motion Capture
Data." Proceedings of Graphics Interface 2000, Montreal, Quebec,
Canada, May 15-17, pp. 53-60.

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Van Der Helm FCT, Analysis of the kinematic and dynamic behaviour of the
shoulder mechanism" J. Biomech. 27: 527-550, 1994.

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"Paolo de Leva" wrote:

a simple (yet obviously not extremely accurate) method for locating the
shoulder joint center, was described in the following paper:

de Leva, P. (1996). Joint center longitudinal positions computed... Journal
of Biomechanics 29.

Rick S. Hall, M.Sc. Email: rickh@sfu.ca

Centre for Injury Prevention and Mobility
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School of Kinesiology
Simon Fraser University
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