The network of nerves that start at the spinal cord and control the shoulder, elbow, wrist, and hand is called the brachial plexus. These nerves act like the electrical wiring system of a car and carry messages from the body to the brain. The nerves, themselves, are like electric wires wrapped up in insulation.
There are two types of nerves: motor and sensory. The motor nerves carry messages to the muscles from the brain and make them move the body. The sensory nerves carry temperature, pressure, and pain messages from the body up to the brain. The brachial plexus contains nerves of both types.
Damage or Injury
The brachial plexus network can be damaged by being cut, stretched, or injured by pressure. It can be stretched when the head and neck are violently moved from the shoulder. If the movement is drastic enough, the nerves can even have their roots in the neck torn out, or avulsed. If the brachial plexus is crushed between the collarbone and ribcage, or if muscles are injured and swell, the brachial plexus can be damaged by the resulting pressure.
If any nerve is injured and can no longer send or receive messages to the brain, hand and arm muscles may stop working and result in a loss of feeling in the affected area. A cut nerve has both the nerve and its insulation cut, but a nerve that has been damaged by stretching or pressure leaves the insulation intact and only stops the nerve fibers from sending or receiving messages.
If the nerve is cut, but the insulation stays healthy, the end farthest from the brain dies. The end of the nerve nearest the brain survives and may even begin to heal and grow new fibers over time.
Some injuries to the brachial plexus are minor ones and can completely heal in several weeks, but others are so severe that the arm may be permanently disabled.
Treatment of the Brachial Plexus
Time and therapy can often fix injuries to the brachial plexus, although this can take weeks or months. If the injured nerves are unlikely to recover on their own, there are several different surgical procedures that may help. The strength of the muscles and quality of sensation in the hand will be examined to detect which injuries are more likely to heal on their own. Additionally, MRI or CT scans might be used to examine the appearance of the brachial plexus, and a Nerve Conduction Study/Electromyogram or NCS/EMG test may be used to see how much electrical activity the nerves and muscles generate.
Depending on the extent of the injury, the affected nerve can sometimes be repaired or replaced by an undamaged nerve from somewhere else in the body. If the damaged nerve is a motor nerve that is used to control muscle movement, functioning muscles or a transfer of tendons can be used to return function to an affected area.
Recovery & Therapy
To keep the muscle lively and prevent joints from becoming stiff and inflexible, therapy may be recommended. The goal of therapy is to keep the joints from stiffening up. Since sensation is lost when a nerve is injured, extra care must be taken to avoid cutting or burning the fingers. Any pain will either be greatly reduced or eliminated altogether, so watching the area may be the only way to know if an injury has occurred. Even after the nerve has recovered, a procedure known as sensory re-education may be needed to remind the brain about how to respond to messages sent from the hand or finger. Therapy that is appropriate for the nature and extent of your injury will be recommended.
Exactly what is lost or affected after an injury to the brachial plexus depends on several things. In addition to the type of injury sustained and its location and severity, age can sometimes be a factor. Injuries to the brachial plexus may produce long-lasting or even permanent problems. Fortunately, proper therapy and care furnished by a knowledgeable hand surgeon or arm physician can help you keep as much function as possible.