Matching Canals and Muscles

There are three canals which are aligned
with the three conjugate muscle pairs.

Horizontal > ipsilateral MR & contralateral LR
Anterior > ipsilateral SR & contralateral IO
Posterior > ipsilateral SO & contralateral IR

This allows the eye to rotate about any axis in three dimensions: horizontal, vertical or torsional

E.g. rolling the head, right ear down, activates the anterior and posterior canals on the right.

This in turn activates the SR & SO on the right side and the IR and IO
on the left side.
The result is a counterroll (torsional) of both eyes.

Copyright © 1996 Tutis Vilis and Douglas Tweed
University of Western Ontario
London Ontario Canada
Updated October 28, 2005

Comments welcome. Email to tutis.vilis@schulich.uwo.ca