To analyze knowledge of the anatomic location of the piriform fossa using a questionnaire with anatomic figures.

Participants taking AO Trauma Brasil courses were requested to complete a questionnaire containing a photograph of the superior surface and a photograph of the lateral surface of the femur and answer a question asking which of four numbered points corresponded to the piriform fossa.

Just 4.5% of respondents correctly chose point 2 (the piriform fossa) in both images, while 75.4% of respondents chose point 4 (the trochanteric fossa) as the correct anatomic structure. The subset of 4th-year residents' answers was significantly different from those of the other subsets, with 7.5% of correct answers.

The low rate of correct answers indicates a tendency for the respondents to be influenced by illustrations in text books or examples in scientific publications that indicate the site of the piriform fossa incorrectly. Interest in the specialty of traumatology is possibly the reason why the subset of 4th-year residents had a better- than-average rate of correct answers.