Fig. 1

Duane retraction syndrome type 1 in the left. a Ocular versions demonstrating limited abduction, fissure narrowing on attempted adduction and a small upshoot in the left eye. b-d Three consecutive thin-section T2-weighted images show the normal right abducens nerve (arrows) as a dark structure emerging from the pontomedullary junction (b), coursing superiorly and obliquely (c), and finally entering the Dorello’s canal (d). The left abducens nerve is not identified. e Coronal T2-weighted image of the orbit shows extraocular muscles in normal size. f Ocular versions demonstrating full abduction and a small upshoot in the left eye