Brachial plexus palsy is caused by a birth injury to the brachial plexus, the nerve network that controls movement and sensation of the arm. The main result of this injury is weak or paralyzed muscles in the shoulder, arm, and hand. Fortunately, most infants with this condition make complete spontaneous recovery. Some, however, are left with varying degrees of arm weakness.
Among infants who do not recover spontaneously, some will require physical therapy and occupational therapy only, and others will need both therapy and surgery. Children who develop deformities in the shoulder, arm, or hand may need orthopaedic treatment. In all cases, treatment must be started early to ensure the greatest improvement.