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.
Erb-Duchenne (Erb's) palsy refers to paralysis of the upper brachial plexus.
Dejerine-Klumpke (Klumpke's) palsy refers to paralysis of the lower brachial plexus.
Although injuries can occur at any time, many brachial plexus injuries happen when a baby's shoulders become impacted during delivery and the brachial plexus nerves stretch or tear.
There are four types of brachial plexus injuries: avulsion, the most severe type, in which the nerve is torn from the spine; rupture, in which the nerve is torn but not at the spinal attachment; neuroma, in which the nerve has torn and healed but scar tissue puts pressure on the injured nerve and prevents it from conducting signals to the muscles; and neuropraxia or stretch, in which the nerve has been damaged but not torn. Neuropraxia is the most common type of Brachial plexus injury.