Suprascapular nerve lesions

Causes

• Traumatic:
  • Proximal upper brachial plexus injury by forceful depression of the shoulder.
  • Fracture of suprascapular notch.
  • Injury by repetitive overhead motion (eg. tennis, volleyball, weight lifting).
• Entrapment neuropathy (ganglia, cysts).
• Iatrogenic (rotator cuff repair surgery).
• Parsonage-Turner neuralgic amyotrophy.

Symptoms & signs

• Shoulder pain exacerbated by external rotation and/or abduction of humerus.
• Weakness and atrophy of supra- and infraspinatus muscles.
• Numbness in upper lateral shoulder.

Examination

• Test abduction strength against resistance. Supraspinatus assists mainly in the first 15 degrees in abduction.
• Inspect supra and infraspinatus for signs of atrophy.
• Test for sensory deficit in upper lateral shoulder.
• If pain exists, observe pattern and exacerbating movements.