The brachial plexus is a network of nerves that conducts signals from the spine to the shoulder, arm, and hand. Brachial plexus injuries are caused by damage to those nerves.

Symptoms may include

• A limp or paralyzed arm
• Lack of muscle control in the arm, hand, or wrist
• Lack of feeling or sensation in the arm or hand

Brachial plexus injuries can occur as a result of shoulder trauma, tumors, or inflammation. Sometimes they happen during childbirth when a baby's shoulders become stuck during delivery and the nerves stretch or tear.

Some brachial plexus injuries may heal without treatment. Many children who are injured during birth improve or recover by 3 to 4 months of age. Treatment includes physical therapy and, in some cases, surgery.

NIH: National Institute of Neurological Disorders and Stroke