How would someone put on Tefillin if r"l his non-dominant arm was replaced by a prosthetic from the shoulder?
- Would the halachos be the same as a cast or other obstruction? Or perhaps this case is worse, since in those cases the person has an arm, just that there's something in the way?
- If the answer to #1 is that one should not put Tefillin on the prosthetic arm, is there any benefit to putting Tefillin on the biological arm, even though it's the person's dominant arm?
- If the answer to #2 is that one should put Tefillin on the dominant arm, what if the person had both of his arms replaced? Is he entirely exempt from Tefillin at that point, or should he put it on one of the prosthetics?
(This answer takes it for granted that one doesn't put Tefillin on a prosthetic arm, but it's unsourced.)