Paralysis of the trapezius muscle: evaluation and surgical management.

Background: Paralysis of the trapezius muscle most commonly results from iatrogenic injury to the spinal accessory nerve.

Methods: The clinical presentation and physical examination findings of trapezius palsy have been well characterized, but unfortunately the diagnosis of this condition is oftentimes missed or delayed, sometimes leading to unnecessary surgery on the rotator cuff or tendon of the long head of the biceps.

Results: The diagnosis can be confirmed using electromyography with nerve conduction studies.