Fig. 1From: Polymyoclonus aggravated by neck flexion as the isolated presenting symptom of Hirayama disease: case reportCervical magnetic resonance images captured with the patient in the supine position (a) were unremarkable, while when the patient was in the flexed position, anterior effacement of the posterior dural sac was observed with venous engorgement at the C6–8 levels (b)Back to article page