Acute Parsonage-Turner syndrome


Rotator cuff denervation syndromes may be due to by a variety of causes, most important are:

  • viral or autoimmune neuritis: Parsonage-Turner syndrome
  • fibrous bands
  • paralabral cyst
  • traumatic nerve injury (stretching/traction injury)

Typical muscular innervations are:

In this case, the distribution of affected muscles doesn't follow a single myotomic innervation, consistent with a polyneuropathy such as Parsonage-Turner syndrome.

Please note that the chronic stage differs in MRI appearance.