Is coordinate of trunk joint force global or local?


In SelectedOutput,there are AnteroPosterior, ProximoDistal and MedioLateral joint forces between every two vertebral disks. Are “AnteroPosterior, ProximoDistal and MedioLateral” global or local? If it is local, which disk the force is referred to? For example, L4L5MedioLateralForce, is the force referred to L4 or L5?

Thank you very much.


The SelectedOutput joint forces are given in local and usually in the proximal segment ref frame of the joint.
If you open the TrunkSelectedOutput.any file you will see that for each joint there is a comment with the reference frame used. So for example you will see that L4L5 force is given in L5 ref frame.

Same thing for the arms and legs.

Best regards, Sylvain.