Abstract
BACKGROUND: The Parks 3-step test is an important test in the diagnosis of a single cyclovertical muscle palsy. PURPOSE: This video is presented to provide a simplified and easy understanding of the Parks 3-step test for post-graduate residents. SYNOPSIS: The video contains a description of the steps to perform a 3-step test, the results of the test in a case of superior oblique palsy, the conditions that mimic a positive 3-step test, and how to identify these mimicking conditions. HIGHLIGHTS: This is a simple demonstration of a classic clinical diagnostic procedure. ONLINE VIDEO LINK: https://youtu.be/1wpjwe19c0E.