means The ulna is the longer of the two forearm bones, running on the pinky side from elbow to wrist, with its top end forming the bony point of the elbow.

from Straight from Latin ulna, meaning 'elbow' or 'forearm.' It belongs to a wide family of arm-and-length words across Indo-European languages — a likely cousin of Greek ōlénē ('elbow') and of English 'ell' and 'elbow' themselves. Fittingly, the same root sense of forearm-as-measuring-stick gave us 'ell,' an old unit of length roughly the span of the lower arm.