tróclea

Trochlea, plural trochleae, is a term used in anatomy to describe a pulley-like, grooved, or spool-shaped structure that guides movement of tendons or forms an articulation with another bone. The word comes from Latin trochlea, meaning pulley, itself from Greek roots.

In the musculoskeletal system, the humeral trochlea is a spool-shaped articular surface at the distal end of the humerus. It articulates with the trochlear notch of the ulna, allowing hinge-like flexion and extension of the elbow. The trochlea lies between the capitulum laterally and the medial epicondyle proximally, and its groove helps to guide the ulna during movement. The femoral trochlea forms the patellofemoral groove on the anterior surface of the distal femur, guiding the patella as the knee flexes and extends.

In the orbital region of the eye, the trochlea is a fibrocartilaginous pulley through which the tendon of the superior oblique muscle passes. This pulley redirects the tendon, enabling the muscle to depress and intort the eye as it contracts.

Clinical relevance includes variations in trochlear morphology that can affect joint tracking and stability, such as trochlear dysplasia contributing to patellofemoral instability. Trauma or fractures involving the distal humerus can involve the trochlear articular surface and impact elbow mechanics. The term trochlea also appears in other anatomical contexts and in descriptions of the trochlear nerve system.