Idiopathic spinal accessory nerve palsy. A case report.

Spinal accessory nerve palsy may lead to dysfunction or paralysis of the trapezius muscle. Common causes are iatrogenic or secondary due to trauma, infection or tumour. Idiopathic palsy is considered extremely rare. We present the case of a 42-year-old Caucasian male suffering from a unilateral, isolated paralysis of his ipsilateral trapezius muscle. There was no related trauma, nor any past history of surgical procedures. An electromyographic study confirmed the idiopathic paralysis of the distal segment of the spinal accessory nerve.