| The brachial plexus is a system of nerves connecting the spinal cord to the shoulder, arm, and hand. These nerves carry neural signals for movement and sensation back and forth between brain and limb. The nerves that connect to the arm exit the spinal cord higher in the column, while those that control the hand and fingers exit lower. Brachial plexus injury is most commonly caused during a childbirth involving shoulder dystocia. During this birth complication, the shoulder of the fetus is obstructed by either the pubic bone or sacral promontory. The impaction, as well as any maneuvers performed to release the shoulder, can stretch the brachial plexus and cause injury. There are different degrees of brachial plexus injury, depending on how severely the region is stretched by shoulder dystocia:
- Neurapraxia – The nerve has been stretched and damaged but not torn.
- Neuroma – The nerve was injured and scar tissue has grown around the injury, which puts pressure on the injured nerve and prevents the nerve from sending signals to the muscles.
- Rupture – The nerve is torn, but the injury is away from where the nerve attaches to the spinal cord.
- Avulsion – The nerve tears away from where it attaches to the spinal cord. Avulsion is the most severe type of brachial plexus injury.
Erb's palsy is another name for an injury to the upper brachial plexus. Erb's palsy primarily affects the major shoulder and arm muscles. Klumpke's palsy is an injury to the lower brachial plexus (more rare). This injury affects the movement of the hand muscles and finger flexors. |
