Elevation deficit caused by accessory extraocular muscle

Abstract

Purpose: To report an elevation deficit, which was caused by an accessory extraocular muscle, in a 6-year-old boy.

Methods: Computed tomography and magnetic resonance imaging were used to confirm an accessory, fusiform, well-defined, solid structure in the retrobulbar space.

Results: A supernumerary intraconal muscle was detected between the annulus of Zinn and the posterior part of the left globe.

Conclusion: This rare anomaly may represent an atavistic retractor bulbi muscle.