• Shoulder pain.
• Numbness of the shoulder, arm, or hand.
• Tingling, burning, pain, abnormal sensations.
  • The location varies with the part of the plexus injured.
• Weakness (decreased muscle strength, independent of exercise) of the arm, hand, or wrist.
  • Unable to extend or lift the wrist (wrist drop).
  • Hand weakness.
• If caused by a lung tumor compressing the plexus, there may be associated Horner's syndrome (eye drooping and decreased sweating in the face and small pupil).

Neuromuscular examination of the arm, hand, and wrist indicates brachial plexus dysfunction. Reflexes may be abnormal in the arm. Specific muscle losses may indicate the portion of the brachial plexus that has been damaged.

Variable deformities may develop in the arm or hand, and loss of muscle mass (atrophy) may be profound. Detailed history may be needed to determine the possible cause of the problem.

Tests that reveal brachial plexopathy may include:

• Nerve conduction test and electromyography (NCS/EMG), which is a recording of the electrical activity of nerves and muscles.
• Nerve biopsy -- indicating systemic diseases that may affect the brachial plexus.