How and why would they grasp the Kohen Gadol's shoulder stones?

Question

Mishnayot Tamid 7:1 says that if the Kohen Gadol entered the Heichal to prostrate himself during the daily service, an honor guard of three kohan would assist him:

בִּזְמַן שֶׁכֹּהֵן גָּדוֹל נִכְנָס לְהִשְׁתַּחֲווֹת, שְׁלשָׁה אוֹחֲזִין בּוֹ, אֶחָד בִּימִינוֹ, וְאֶחָד בִּשְׂמֹאלוֹ, וְאֶחָד בַּאֲבָנִים טוֹבוֹת

When the Kohen Gadol entered to bow, three would hold him, one on his right side, one on his left side and one held on to the precious stones.

R' Ovadia miBartenura explains what "precious stones" we're talking about:

שעל כתפות האפוד

That are on the shoulders of the Apron

The Kohen Gadol's apron had an onyx stone fastened on each shoulder. You can see an artist's rendition of them in this Chabad.org illustration.

It seems to me that it would be quite awkward to help the Kohen Gadol walk by holding these stones.

• Why specifically would the other kohen help by supporting these stones? Is there symbolic significance?

• How would the other kohen grasp the stones?

  • Would he pinch-grip them from above? That sounds difficult.

  • Would he slip his hands under them, between them and the Kohen Gadol's shoulders? I expect that would create an improper separation between the Kohen Gadol and his holy vestements.

Answer 1

According to this shiur by R. Yosef Carmel (see footnote 15), the assisting Kohen would hold on to either the stones on the shoulder straps of the ephod or the front of the stones of the choshen.

The point of this was to prevent the choshen and the urim vetumim which it contained from coming into direct contact with the ground while the Kohen Gadol was prostrating himself.

Answer 2

The Rosh in the "Gemara" on Tamid Daf 33b says that they held the breastplate with the stones.

Same explanation given by the "Rashi" there.

Unclear why the Bartenura says what he does. And the Yachin says the same thing.