ELEVATION DEFICIT CAUSED BY ACCESSORY EXTRAOCULAR-MUSCLE

PURPOSE: To report an elevation deficit, which was caused by an access ory extraocular muscle, in a 6-year-old boy. METHODS: Computed tomogra phy and magnetic resonance imaging were used to confirm an accessory, fusiform, well-defined, solid structure in the retrobulbar space. RESU LTS: A supernumerary intraconal muscle was detected between the annulu s of Zinn and the posterior part of the left globe. CONCLUSION: This r are anomaly may represent an atavistic retractor bulbi muscle.