What does trochlea mean?
A trochlea is a pulley-shaped anatomical structure. Its best-known use is the fibrous ring inside the orbit, where the tendon of the superior oblique muscle changes direction as it passes through. The word can also describe spool-shaped parts of bones and joints, such as the trochlea of the humerus at the elbow. In mechanical contexts, a trochlea is a grooved wheel used in a pulley. The term is formal and specialized rather than everyday vocabulary, but it is useful when precision matters because it identifies a structure whose function is to redirect force or movement. It should not be confused with the trochanter, which is a bony prominence rather than a pulley-shaped structure.
nounA pulley-shaped anatomical structure, especially the fibrous ring in the eye through which the tendon of the superior oblique muscle passes. More generally, it may refer to a spool-shaped part of a bone or joint.
- An anatomical pulley-like structure, especially the trochlea of the humerus at the elbow.
- The fibrous ring in the orbit through which the tendon of the superior oblique muscle passes.
- A grooved wheel or pulley, especially as part of a mechanical system.
"The superior oblique tendon passes through the trochlea before turning back toward the eye."
"The trochlea of the humerus articulates with the ulna at the elbow."
"In the eye, the superior oblique tendon loops through the trochlea, which redirects the muscle's pull."
The traditional anatomical plural is trochleae; trochleas is also accepted in general use.
"The trochleae of the humeri form the elbow's pulley-shaped articulations."
A tiny ring inside the eye works like a pulley, turning the superior oblique tendon in a direction that helps the eye rotate.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of trochlea
The word comes through Latin from Ancient Greek, where trochléa referred to a pulley or wheel and was related to Greek trochlos, meaning “wheel.” That form is connected with trepein, “to turn,” reflecting the wheel's turning motion. The Greek root also underlies related forms such as trochoid, tropism, and trophy.
Related word forms
How trochlea is actually used
This is primarily a formal anatomical and technical term. In medicine it is used for several pulley-shaped structures, so the surrounding bone, joint, or muscle may need to be specified.
Easily confused with trochlea
A trochlea is a pulley-like anatomical structure, whereas a trochanter is a prominent bony projection, such as one on the femur.