A previously unreported method of measuring three-dimensional motion of
joints, applied to two elbows obtained post mortem, showed that during
flexion there is a continuous and linear change in the carrying angle, the
forearm going into varus angulation as elbow flexion progresses. In
addition, internal axial rotation of the forearm occurs near the beginning
and external axial rotation, toward the end of flexion. With the elbow
extended, the ulna shows little tendency to deviate laterally or to rotate
axially during pronation and supination. The axis of rotation during elbow
flexion lies approximately at the center of the trochlea.