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  • MODELLING THE SHOULDER COMPLEX - Epilogue

    9 August 1993

    Dear BIOMCH-L Subscribers,

    About 11 days ago, I posted a request for information regarding the
    shoulder complex. I would like to first, thank all of the responders
    who took time from their busy schedules to share with us their advice
    and experiences in this area. Second, as promised, what follows is a
    summary (slightly edited) of the responses we received.

    Thank you,

    Drew Smith, PhD AWSMITH@UTCC.UTORONTO.CA

    Director of Research
    Lyndhurst Spinal Cord Centre
    520 Sutherland Drive
    Toronto Ontario CANADA
    M4G 3V9 (416) 422-5551 x3041/3040 FAX (416) 422-5216

    ********* SUMMARY OF RESPONSES RE: SHOULDER BIOMECHANICS **********

    1)
    Date: Fri, 30 Jul 1993
    From: Jonathan Dingwell

    In regards to the shoulder complex, and the kinematics in particular,
    there are several excellent papers written by A. E. Engin on modelling
    of the shoulder complex. I have the papers at home and will bring in
    the actual references on Monday, and send them to you. If you want to
    look for them between now and then, try the J. Biomechanics, between
    1980 and 1986 (or so).

    2)
    Date: Sat, 31 Jul 1993
    From: winters@pluto.ee.cua.edu (Jack Winters)

    Frans van der Helm is here through November, working with me. He's from
    a group at Delft that is VERY active in the shoulder. He's at the smae
    e-mail address: helm@pluto.ee.cua.edu

    Jack Winters

    3)
    Date: Sun, 1 Aug 1993
    From: "JOSEPH.MURPHY"

    This is a brief response to your request posted on the list.
    DuPuy Thackery is a company in England which we have frequent
    dealings with. I know that they are researching into the
    viability of shoulder prosthesis and given the complex nature
    of the joint have done extensive engineering studies.
    Since they are a commercial concern such data might be difficult
    to tease from them. But you never know, a joint research
    project might yeild useful source of capital? ...

    ----------------------------------------------------------
    | "JOSEPH.MURPHY" |
    | |
    | Department of Orthopaedic Surgery |
    | The Queen's University of Belfast |
    | Tel: +44 232 669501 x2823 Fax: +44 232 661112 |
    | |
    | "We must learn to live together as brothers |
    | or perish together as fools" |
    | - Martin Luther King Jnr |
    | |
    |Opinions expressed here are personal and in no way be |
    |considered as representing the institution above. |
    ----------------------------------------------------------

    4)
    Date: Sun, 1 Aug 1993
    From: BI_RSMITH@cchs.su.edu.au

    ... Sandy Nicol is doing some work in this
    area from Srathclyde. Also from Delft is Pronk (1991) The shoulder girdle
    analysed and modelled kinematically. Johnson and Stuart, University
    of Newcastleupon Tyne, UK have used Pronk's method. Dirkjan Veeger
    from Vrije Universiteit Amsterdam also developed a method, modelled
    from known static positions which he reported on here at our Human
    Propulsion Conference. ...

    Richard.

    5)
    Date: Mon, 2 Aug 1993
    From: H=E=J=Veeger%FA%FBW@Zeus.fbw.vu.nl

    ..

    Information on modelling of the shoulder complex can also be found in the
    publication in Clinical Biomechanics 1993;8 81-90 (Veeger & Van der Helm,
    Orientation of the scapula in a simulated wheelchair push"


    Yours,

    DirkJan Veeger

    6)
    Date: Mon, 2 Aug 1993
    From: helm@dewey.ee.cua.edu

    Dear Drew,

    As a response to your posting at BIOMCH-L, I am happy to see that
    the shoulder research work at Delft University has caught your eye.
    The questions that you've raised are very valid questions, and
    require a much more elaborate discussion than that is feasible by
    e-mail. Therefore, I will give you a short opinion from my side, and
    a brief outline of the present research at Delft and the
    cooperating universities in the Dutch Shoulder Group, i.e. the Dept.
    of Orthopaedics, Leiden University, and Fac. of Human Movement
    Sciences, Free University Amsterdam.

    1) Motion analysis of the shoulder girdle bones is extremely
    difficult. External marker systems will not work, and 3D X-ray
    requires markers implanted in the bones. We are using a static
    method, in which bony landmarks are palpated and the 3D coordinates
    are subsequently recorded. Then the position of the bone can be
    reconstructed. The accuracy of the method is estimated to be 2-6 mm
    standard deviation per coordinate of bony landmarks, well within the
    (assumed) accuracy of video systems, in which the markers will move
    with respect to the bones underneath.
    Currently, we are extrapolating these static measurements to dynamic
    situations. The justification for this procedure is tested using
    X-ray films at Leiden University.

    2) Strength measurements of individual muscles are not feasible for
    the shoulder region (are they for any other part of the human
    body?) without using some sort of a musculoskeletal model.

    3) In Delft a very detailed musculoskeletal model of the shoulder
    region has been developed, consisting of the thorax, clavicle,
    scapula and humerus. Muscles are represented by a total of 95 muscle
    lines of action, some of them wrapped around underlying bony
    contours. The model has been applied for inverse static and inverse
    dynamic situations, i.e. bony motions are input and the muscle
    forces (or neural input) are calculated. For the inverse dynamic
    situations a 3rd order non-linear muscle model is used (see e.g.
    Winters & Stark, 1985), with roughly approximated muscle properties.
    Currently, the latter approach is used for calculating muscle forces
    for manual wheelchair propulsion, in a joint project with Free
    University Amsterdam.

    4) Presently, I am working at Catholic University of America,
    Washington D.C., with prof. Jack M. Winters. Our goal is to develop
    forward static and forward dynamic optimization algorithms for
    shoulder motions. Part of the work is to assemble all available
    knowledge of muscle, ligament and joint properties of the shoulder
    region.

    5) For your problem of spinal cord lesions, I can foresee two
    approaches.

    - inverse static/dynamic simulations, for which the shoulder girdle
    motions must be recorded. This will be very interesting anyway for
    this particular group of patients. Muscle forces can be estimated by
    optimization procedures taking into account which muscles are
    paralysed.

    - forward static/dynamic simulations, with the same restrictions to
    neural input as the first approach. However, the optimization of
    these simulations is still under investigation.

    6) My PhD-thesis, and two other recent PhD-theses from Delft
    University of Technology will be sent to you, e.g.:

    - Gijs M. Pronk (1991): The shoulder girdle, analysed and modelled
    kinematically.

    - Riender Happee (1992): The control of shoulder muscles during goal
    directed movements.


    I hope that this information will give you an idea of the work in
    the Dutch Shoulder Group. There are a number of other projects
    related to the subject. If you want more information, I will be
    pleased to help you.
    Application of the shoulder research to persons with spinal cord
    lesions sounds very interesting to me. We are willing to share our
    information, or help you out in another way. Maybe we can join our
    common interest in the shoulder in a research project?

    With kind regards,

    Frans C.T. van der Helm
    Dept. of Mechanical Engineering
    Catholic University of America
    620 Michigan Ave., N.E.
    Washington, D.C.
    U.S.A.
    tel. (202)-319-5170
    fax. (202)-319-4499
    e-mail: helm@pluto.ee.cua.edu

    As of November 1, 1993:
    Dept. of Mechanical Engineering and Marine Technology
    Delft University of Technology
    Mekelweg 2
    2628 CD Delft
    The Netherlands
    tel. (+31)-15-783812
    fax. (+31)-15-784717
    e-mail: wbmrasp@dutrex.tudelft.nl

    7)
    Date: Mon, 2 Aug 1993
    From: mys@ip.chalmers.se (Mats Svensson)

    A thesis on muscle strength was presented by Dan Karlsson at Chalmers
    University of Technology in G|teborg, Sweden.

    Dan Karlsson (1992): Force Distributions in the Human shoulder. Chalmers
    University of Technology, Division of Mechanics, G|teborg, Sweden,
    ISBN 91-7032-704-1


    You can probably get a copy from:
    Mrs Gunilla Ekman
    Div. of Mechanics
    Chalmers University of Technology
    S-412 96 G|teborg
    Sweden

    Tel: +46 31 772 1515
    Fax: +46 31 772 3477

    Best wishes,

    Mats Svensson

    8)
    Date: Mon, 2 Aug 1993
    From: MEHTA01@swmed.edu

    ..

    I am trying (in my spare time) to carry out a rough estimate analysis of
    forces on the humerus when in a certain posture. I am interested in this
    problem due to a number of accidents being reported in my favourite sport:
    hang-gliding ... where the humerus fractured in flight and during landing.

    ... Could you possibly suggest the
    best source for muscle orientation and action at the shoulder joint?

    Thank you.

    SHreefal Mehta

    9)
    Date: Tue, 3 Aug 1993
    From: "Arthur E. Chapman"
    To: awsmith@utcc.utoronto.ca

    .. We are currently compiling a set of data from serial MRI scansof
    the upper limb inorder to produce a model of the same which is amenableto
    simulation. We have found that the Dutch group of Rozendal et al. at the
    free UNiversity have made some strides in this direction. I should look up
    their work. We haven't really faced the problem of the shoulder yet.
    Best regards,
    Arthur

    10)
    Date: Wed, 4 Aug 1993
    From: "G.R.Johnson"

    .. We also have a considerable interest in shoulder biomechanics. In
    particular we have used the 3space isotrak system to study both humeral
    and scapular movements using a palpator technique (Clin Biomech in press).
    In conjunction with Univ of Newcastle NSW I have carried out a detailed
    dissection study of 6 shoulders and digitised the points of attachemtn of
    all muscles from radiographs. One paper on this is in press with Clin
    Biomech nad we have published a paper on the measurement technique in J
    Biomed Eng 1992, Vol 14, 490-494. The definitive paper on coordinate
    attachments is in preparation for J Biomechanics and we hope to submit in
    September or so. ...

    I have a research student starting in October to look at the load bearing
    charactersitics of the shouoder girdle in more detail.

    ..

    Garth Johnson
    Dept of Mech Eng
    University of Newcastle upon Tyne
    Newcastle upon Tyne NE1 7RU

    tel: +44-91-222-6196
    fax: +44-91-222-8600
    email:g.r.johnson@newcastle.ac.uk

    11)
    From: Ulrich Berlemann

    understanding the problems you are facing with the dynamic shoulder modelling I
    at least have one good news for you: we recently have been in contact with the
    Delft University in the Netherlands regarding the thesis you mentioned in your
    mail. The Dutch have been so kind to send us a copy of it, which is now
    available in our library. I would suggest that you do the same and contact

    Dr. C.W. Spoor
    Delft University of Technology
    Lab. for Measurement and Control
    Mekelweg 2
    2628 CD Delft
    The Netherlands

    ..

    Best wishes from Bern, ULILI@MEM.UNIBE.CH
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