PS

*sur(u)m- - intestine (SED I No. 237)

Inter-Semitic loans (Akk. > Syr. > Arb.) cannot be entirely ruled out.

Akkadian
surummu - a part of the intestinal tract (CAD S 416; AHw. 1063)
Translated as ‘Mastdarm’ in AHw.
Syriac
šurmā - anus, rectum (LSyr. 809, SL 1536)
Scarcely attested.
Arabic
surm- - anus (BK 1 1084, Lane 1352)
Arabic
saram- - pain of the anus (BK 1 1084, Lane 1353)
May be related.
Selti
šērmo - meat of the tail of the sheep (EDG 585)
May be related, but semantically difficult to compare.