Juvenile asymmetric segmental spinal muscular atrophy (Hirayama's disease): three cases without evidence of "flexion myelopathy"

Acta Neurol Scand. 2001 Nov;104(5):320-2. doi: 10.1034/j.1600-0404.2001.00074.x.


Compression of the cervical spinal cord during neck movements ("flexion myelopathy") was proposed to be the main pathomechanism of juvenile asymmetric spinal muscular atrophy (JASSMA). We present 3 patients with the clinical appearance of JASSMA and typical high-intensity signals in the anterior horn cell region of the lower cervical spinal cord (T2-weighted magnetic resonance images) but without evidence of dynamic spinal cord compression. In all these patients pathomechanism distinct from mechanical damage must be assumed.

Publication types

  • Case Reports

MeSH terms

  • Adolescent
  • Cervical Vertebrae
  • Female
  • Humans
  • Magnetic Resonance Imaging
  • Muscular Diseases / etiology*
  • Spinal Cord Compression / etiology*
  • Spinal Muscular Atrophies of Childhood / complications*