Dose of Halacha

Question: I'm left-handed and accidentally picked up my brother’s tefillin . Do I need to remove the retzua from the shel yad and reinsert it the other way so that the kesher faces inwards? Answer: The Terumas Hadeshen (49) writes that there were once two accepted customs regarding the regarding the orientation of the tefillin shel yad . The communities of Rhineland positioned the maavarta , the passage through which the retzua passes, towards the shoulder, with the bayis towards the hand. The communities of Austria followed the opposite practice. The Beis Yosef (OC 27:1) notes that, in his time, the universal custom had become that of the Rhineland communities. He therefore rules in the Shulchan Aruch (OC 27:3) that the maavarta should be towards the shoulder and the bayis towards the hand. The Chayei Adam (1:14:13) writes that if a left-handed person is wearing the tefillin shel yad of a right-handed person, he should ideally remove the strap and reinsert it from ...