It occurs when there is damage to the brachial plexus , an area where the nerve from the spinal cord splits into the individual arm nerves. It may be related to pressure caused by congenital abnormalities that affect the cervical ribs, tumors, or injury by toxins , chemicals, or drugs.
Prevention is varies, depending on the cause.
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. Detailed history may be needed to determine the possible cause of the neuropathy. Tests are guided by the suspected cause of the dysfunction, as suggested by the history, symptoms presented, and pattern of symptom development.