ELBOW  , in

anatomy, the articulation of the humerus, the bone of the upper arm, and the ulna and radius, the bones of the fore-arm (see JOINTS) . The word is thus applied' to things which are like this joint in shape, such as a sharp bend of a stream or river, an angle in a tube, &c . The word is derived from the O . Eng. elnboga, a combination of eln, the forearm, and boga, a bow or bend . This combination is common to many Teutonic languages, cf . Ger . Ellbogen . Eln still survives in the name of a linear measure, the " ell," and is derived from the O . Tent. alma, cognate with Lat. ulna and Gr . 1.M v 1, the forearm . The use of the arm as a measure of length is illustrated by the uses of ulna, in Latin, cubit, and fathom .