\Troch"le*a\, n. [L., a case or sheaf containing one or
more pulleys, Gr. ?. See {Trochilics}.]
1. (Mach.) A pulley. [Obs.]
2. (Anat.) A pulley, or a structure resembling a pulley; as,
   the trochlea, or pulleylike end, of the humerus, which
   articulates with the ulna; or the trochlea, or fibrous
   ring, in the upper part of the orbit, through which the
   superior oblique, or trochlear, muscle of the eye passes.