Radiologically manifested accessory extraocular muscles in thyroid eye disease.

The authors describe 3 patients with Graves orbitopathy who all have accessory orbital structures on orbital imaging. These structures are isodense on CT and isointense on MRI to the extraocular muscles and have a similar anatomical appearance to accessory extraocular muscles previously described in the literature. The authors propose that Graves orbitopathy involves these accessory muscles and makes them visible on imaging.