Trochlea

Trochlea (Latin for pulley) is a term in anatomy. It refers to a grooved structure reminiscent of a pulley's wheel.

Most commonly, trochleae bear the articular surface of saddle and other joints: It also can refer to structures which serve as a guide for muscles:
 * Trochlea of humerus
 * Trochlear process of the Calcaneus
 * The area where the tarsometatarsus articulates with the proximal phalanges in a bird's foot
 * Trochlea of superior oblique (see also superior oblique muscle). This use is the source of the name for the Trochlear nerve.