Hirayama disease in unilateral and bilateral forms-3 case reports

Hirayama disease is a benign, nonprogressive motor neuron disease affecting the upper limbs. It is secondary to an abnormal anterior displacement of the posterior dura with secondary compression of the lower cervical spinal cord. It should be suspected in young male patients with a chronic history of weakness and atrophy involving the upper extremities followed by clinical stability in few years. The involvement is usually unilateral but may be bilateral. MR imaging is the best way to make the diagnosis but it necessitates the use of both extension/flexion and post contrast studies.