The “Crab” Memory Tool for the Actions of the Extraocular Muscles

Introduction: Understanding the primary, secondary and tertiary actions of the vertical recti and oblique muscles is important in the diagnosis of various types of strabismus (superior oblique palsy, A- and V-patterns). Unfortunately, learning these actions can be very challenging. We designed a visual memory tool, and assessed its usefulness for medical students. Methods: Medical students undergoing their rotation in ophthalmology were taught the actions of the extraocular muscles either without the memory aid (control group) or with it (test group). The students were surveyed one week and one month later to determine their ability to recall the muscle actions and asked to subjectively rate the usefulness of the memory aid. Results: Approximately 40% of the test group used the memory tool. Eighty-seven percent of the respondents recommended that the memory aid be taught in the future. Overall, there was no significant difference in the ability to recall the actions of the muscles between the control and test groups. However, those students who found the memory aid helpful had significantly better recall than those who did not. Conclusion: The memory aid may be useful to a significant proportion of students.