The brachial plexus is the network of five nerves that sends signals from the spinal cord (from the C5, C6, C7, C8 and C11 nerve roots) to the chest, shoulder, arm and hand. The brachial plexus therefore controls arm, hand and shoulder movements, as well as all power, function and sensation in those body parts.
Symptoms associated with brachial plexus injuries can differ depending on which of the five nerves are affected and the severity of the injury. Common symptoms include:
Injuries to the brachial plexus occur when some or all of the nerves are traumatised through stretching (neuropraxia), compression, ripping or being torn away from the spinal cord. Injuries may be partial (affecting two or three nerves) or complete, affecting all five nerves.
Brachial plexus injuries commonly occur during motor vehicle accidents, gunshot or stab injuries, contact sports or heavy physical labour. However, injuries can also arise from inflammatory or compressive causes; for example, during the delivery of a baby or due to an individual being in a stretched position for a prolonged period of time.
Brachial plexus injury (BPI) is a common complication associated with shoulder dystocia, which can occur during childbirth. The injury arises when additional obstetric manoeuvres are required to complete the delivery of a baby after the head has been delivered. The shoulders can become stuck behind the mother’s pelvic bone, preventing the delivery of the body.
Approximately 10% of babies who have shoulder dystocia suffer a BPI, the most common of which is called Erb’s Palsy (paralysis of the arm). With prompt treatment and management, most cases of obstetric BPI improve without permanent disability within hours or days; however, around 1% of infants with shoulder dystocia will suffer prolonged or permanent complications.
The brachial plexus is also at risk of injury in patients requiring prolonged ventilation in a prone position (when a person lies face down) in intensive care. This arises when asymmetrical arm positions cause the nerve to become stretched, particularly when the head is excessively flexed to one side. Care should therefore be taken to protect the nerves by maintaining neutral alignment of the cervical spine and to avoid extension of the neck and shoulder. Padding should also be considered to protect the local nerve anatomy from compression injuries.
As a patient recovers and regains consciousness, early identification of any upper limb weaknesses should be monitored and, if necessary, treated. If left untreated, significant and long term symptoms can arise as a result.
Treatment options will again depend on how many of the five nerves are affected and whether the injury is partial or complete. Both partial and complete injuries can be treated with surgery, which would involve either nerve grafting or nerve transfer techniques. For the best results, surgical repair is recommended within four to six months of the injury.