(CBS) — Sue — the Tyrannosaurus Rex at the Field Museum — is giving scientists a helping hand as they try to answer the question: Did carnivorous dinosaurs like Sue ever use those tiny arms?

At the Field Museum on Thursday there was an amputation.

“A temporary amputation. We took the right arm of Sue off. That’s the most complete T. Rex arm known,” explains Bill Simpson, head of geological collections.

Sue’s arm will be examined at Argonne National Laboratory with something that’s like a very high-tech CT scan. Experts will try to determine if Sue ever used her small arms.

That would help answer whether any dinosaurs with small arms ever used them.

“Bones that are used are put under some stress, and that stress causes what we call remodeling of the bone. So the bone basically changes in response to its use,” Simpson says.

Sue is getting her arm back next week.

If it’s determined that Sue actually did use her arms, Simpson says that still doesn’t answer the question: for what?