The Torah prohibits the act of “building” or attaching of any structure that is built firmly or tightly, or requires artisanship to craft (Shulchan Aruch 313)

The question is though, that there are exceptions for things that are easily removable or meant to be removed or reattached, that it would be permitted to attach and detach (Shulchan Aruch 313:6).

Does a prosthetic fit into this exception? On the one hand it is very tight and secure. But on the other, it is also often removed (to clean the arm, for showers etc.) is that called something that is meant to be re-attached?

  • @Kazibácsi how does a walking cane help for this q? The question is about attachment. Does one attach a cane to themselves? Commented May 31, 2018 at 11:36
  • Obviously not, but without cane those people couldn't walk either. See this one: dailyhalacha.com/m/halacha.aspx?id=915 Commented May 31, 2018 at 12:16
  • @Kazibácsi and therefore it’s permitted to make the attachment? How does one thing have to with the other? Commented May 31, 2018 at 12:34
  • It's a difficult issue (actual parts of the body or just for aesthetic purposes). However, it was discussed in the Mishnah (Shabbat 65b), Orach Chayim 301:15, Shulchan Arukh haRav 301:12. See also this article. Commented May 31, 2018 at 16:36

1 Answer 1


R Abraham S. Abraham discusses a related element in the volume 1 of his Nishmat Avraham pp. 166ff. - a 3-volume sefer of medical halacha.

He explains (based on Shulchan Aruch HaRav) that the assembling of items on Shabbbat is only prohibited if it will definitely not be dismantled on Shabbat (i.e., building a permanent structure). Therefore, according to him, there would not even be a violation of Rabbinic prohibition in assembling something that will be dismantled after use.

He applies it to syringes and needles but it feels it could be applied to a prosthesis as well.

I also saw that R Moshe D. Tendler and Fred Rosner write in their article The physically and mentally disabled - Insights based on the teachings of Rav Moshe Feinstein

Other prostheses, such as artificial limbs, may also be put on, taken off, and worn - even through a public thoroughfare - because these devices are considered part of the person's body.

Both Nishmat Avraham and Shmirat Shabbat KeHilchata (18:15) allow going out and wearing a prosthesis on Shabbat (where there is no eruv).

See also this related article from Ohr (credits to Kazi bácsi for locating it).

Of course CYLOR before applying in practice.

  • What about sefaria.org/…?
    – Heshy
    Commented May 31, 2018 at 12:39
  • 1
    @Heshy what do you mean? that removing hair or nails is like removing a prosthesis? But removing hair or nails with one's hand or mouth is unusual, while removing a prosthesis is k'darko. In any case hair and nails are a tolada of gozeiz not bone
    – mbloch
    Commented May 31, 2018 at 12:43
  • I was focusing on הגודלת, which is forbidden derabbanan because of boneh. (yes sorry I should have been clearer)
    – Heshy
    Commented May 31, 2018 at 12:46
  • @Heshy I understand now. But I don't see the connection between braiding hair and assembling a prosthesis. My point early in the answer was that assembling a prosthesis is not like bone because it is not permanent. I also think braiding hair is a very special case as the gemara in Shabbat 95a explains
    – mbloch
    Commented May 31, 2018 at 12:52
  • @mbloch hair is muttar because it's עומדת לסתירה acc. To tosfos Commented May 31, 2018 at 13:08

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