Elbow pronation/supination

Hi,

I was wondering if the AnyBody upper limb model is able to perform elbow pronation/supination ?

If yes, is there a publication/model which I can refer to?

If no, is there a possibility to modify the Anyscript in order to simulate this DoF.

I saw that you worked with Taiwan National Sport University on the baseball pitch, so I was planning to maybe use Anybody for my study including the elbow pronation/supination but before I would like to know the sequence of DOFs modeled. For instance, is your upper limb model similar to the Dutch Shoulder Model or the Holzbaur model?

Thanks in advance,
Maria Laitenberger

Hi Maria,

Yes. AnyBody arm model includes the elbow pronation & supination DOFs.

And as you mentioned, AnyBody shoulder model is based on the Dutch shoulder model.
Here is the reference of AnyBody’s shoulder model:
http://wiki.anyscript.org/index.php/AnyBody_Body_Model#ShoulderArm

I hope this may help you.

Best regards,
Moonki

Thank you very much Moonki for your quick answer!

I’ve read the link you mentioned as well as the webcast on the shoulder model and it helped me to figure out the AnyBody upper limb model. I also read that the forearm pronation-supination (P/S) model is a combination of multiple joints leading to one DoF representing the P/S DoF as a revolute joint.

As I understand it, there is for flexion/extension:
-1 revolute joint between humerus and ulna (3 constraints in translation, 2 constraints in rotation);

And for pronation/supination:
-1 spherical joint between humerus and radius (3 constraints in translation) at the proximal end of the radius;
-1 sliding-spherical joint between ulna and radius (2 constraints in translation) at the distal end of the ulna;

Is that correct?

If that is correct, I guess it’s possible to obtain, after inverse dynamics, the corresponding axial force between the ulna and radius as well as the 6 torques at the proximal and distal ends acting in P/S. Do you also calculate an equivalent P/S torque?

As mentioned by sylvaincarbes from a previous post (08-16-2011): ‘‘The combination of the proximal spherical joint and the distal sliding-spherical joint is then equivalent to a revolute joint (5 constraints in total)’’. So I was also concerned about the definition of the P/S axis of rotation. How is it defined? Does it pass through the radius proximal end and the ulna distal end?

Thank you very much.

Best regards,
Maria

Hi Maria,

I guess that you may understand how AnyBody shoulder model was constructed well.

Your understanding:

As I understand it, there is for flexion/extension:
-1 revolute joint between humerus and ulna (3 constraints in translation, 2 constraints in rotation);

And for pronation/supination:
-1 spherical joint between humerus and radius (3 constraints in translation) at the proximal end of the radius;
-1 sliding-spherical joint between ulna and radius (2 constraints in translation) at the distal end of the ulna;

These are right.

And you can see the following results by inverse dynamics:

  1. Reaction forces and moments
    ElbowHumeroUlnar_MedioLateralForce
    ElbowHumeroUlnar_ProximoDistalForce
    ElbowHumeroUlnar_AnteroPosteriorForce
    ElbowHumeroUlnar_AxialMoment
    ElbowHumeroUlnar_LateralMoment
    ProximalRadioUlnar_RadialForce
    ProximalRadioUlnar_DorsoVolarForce
    RadioHumeral_ProximoDistalForce
    DistalRadioUlnar_RadialForce
    DistalRadioUlnar_DorsoVolarForce

  2. Moments generated by muscles for elbow's degrees of freedom
    ElbowFlexion
    ElbowPronation

If you want to understand better about AnyBody, then I would recommend you to test with Demo version.

Then also you can find how P/S rotation could be defined.

Best regards,
Moonki