Hello again,
on second thought, it might be best to read the problamtic phrase as a plural: ú-ba-˹na˺-tu uṣ-ṣa „finger-(shaped protrusions) come out”. At least, there are a few attestations for “finger” in the sense of “finger-shaped object” (the word is also used as a designation of a kind of cucumber) listed in CAD, although I think the word meaning in this passage is not closely related to its specific usage in the context of extispicy. Anyway, I’m not convinced anymore of my previous proposition.