Magnetic Resonance Imaging Findings of Hirayama’s Disease

Hirayama’s disease is a rare form of cervical myelopathy resulting in juvenile muscular atrophy of the upper limb. We describe the magnetic resonance imaging findings of Hirayama’s disease in a 20-year-old male, who demonstrates abnormal detachment and forward displacement of the posterior cervical dura during neck flexion, with the lower cervical cord abutting on the posterior border of the lower cervical vertebral bodies. This compression causes ischaemic changes in the lower cervical cord and hence the subsequent denervation and atrophy of the distal upper limb muscles. A high index of clinical suspicion and magnetic resonance imaging of the cervical spine with neck flexion are the key to diagnosis.