Yes, if you need you can say...αντιβράχιο = forearm, βραχίονας/μπράτσο = upper arm,
καρπός = wrist, αγκώνας = elbow.

But for both hand and arm it's "χέρι" unless you need to be more specific they you use one of the above.

There is also παλάμη but that's only "palm" not the whole "hand".