Delayed Unilateral Spinal Accessory Neuropathy after Whiplash Injury - A case report -

Case Report

J Korean Assoc EMG Electrodiagn Med 2014;16(1):32-36.
Published online June 30, 2014.

Received: 30 April 2014 • Revised: 22 May 2014 • Accepted: 22 May 2014

Abstract

Unilateral spinal accessory nerve (SAN) palsy is an uncommon pure motor mononeuropathy. Branches of the SAN innervate the sternocleidomastoid and trapezius muscles. Here, the authors describe the case of a 48-year-old man who presented with left shoulder discomfort with shoulder girdle muscle atrophy after a traffic accident. No limitation in any direction was observed in active or passive range of neck motion. However, the patient presented with left shoulder motor weakness on flexion and abduction and limitation of motion; he complained of shoulder pain during forward flexion, abduction, and external rotation. On physical examination, there were no pathologic reflexes, but the patient complained of a tingling sensation in left shoulder concurrent with atrophic sternocleidomastoid and trapezius muscles. An electrodiagnostic study revealed evidence of a unilateral left spinal accessory nerve lesion. The authors report a rare case of isolated unilateral spinal accessory nerve palsy with delayed shoulder pain after whiplash injury.

Key Words: Spinal accessory nerve palsy, Whiplash injury, Winging scapula