Brachial plexus palsy is a problem with the muscles in a baby’s arm. The brachial plexus is a bundle of nerves that runs between the spine and the arm. If one of the nerves is stretched or damaged, it can weaken the muscle and make it hard for the baby to move the arm.
Often it’s not clear how the nerve was damaged. Sometimes it’s caused by a difficult birth.
The doctor can tell which nerve was affected by noting how the baby moves. The baby may not move the affected arm as much as the other one or may hold his or her hand at an angle.
The affected arm usually gets better in about 3 months. In some cases, the nerve damage can last longer or be a permanent problem.