Background: Anomalous ocular muscle insertions are a rare cause of ocular motility disturbances.
Methods: We report the clinical presentation and the intraoperative findings of two cases with an abnormally nasally inserted superior oblique tendons presenting with a Brown syndrome-like clinical picture.
Results: Case no 1 was a 5-year-old girl presenting with a chin up position. There was bilateral limitation of elevation in adduction, -4 on the right side and -3 on the left side with +1 downshoot on adduction on either side Patient was orthotropic in down-gaze with small V-pattern exotropia. Case no 2 was a 4-year-old boy presenting with an esotropia of 35Δ that was partially corrected with his spectacles to 20Δ. Ductions showed -4 defective elevation in adduction of the right eye. Surgical exploration in both cases revealed abnormal nasal insertion of the superior oblique tendons. The line of insertion had a convexity facing superonasally. The posterior fibers were inserted 7-8 mm posterior and just nasal to the nasal border of the superior rectus insertion, while the anterior fibers were shorter and inserted 5 mm nasal and 4 mm posterior to the nasal edge of superior rectus insertion. In both cases, there was an improvement in the elevation on adduction after superior oblique lengthening.
Conclusions: Abnormal nasal insertion of the superior oblique muscle enhances the depressor effect of the muscle and can create a Brown-like picture.
Keywords: Abnormal path; Brown syndrome; nasalization; sagittalization; superior oblique.