The brachial plexus is a network (bundle) of nerves in the shoulder and under the arm. The network is composed of the nerves that carry signals from the spinal cord to the shoulder, arm, hand, and fingers. These signals transmit information between the brain, the spinal cord, and the arm and hand and are required for typical movement and feeling (sensation). If nerves in the upper part of the brachial plexus bundle are damaged, the injury is called Erb’s (or Erb-Duchenne) Palsy. If the nerves in the lower part of the brachial plexus are damaged, the injury is called Klumpke’s (or Dejerine-Klumpke) Palsy. In some instances, all the nerves may be damaged, resulting in "global" palsy.
Injuries to the brachial plexus result in movement and sensation difficulties in the arm, which may be mild or severe, and temporary or prolonged. Brachial plexus injury occurs in approximately 1.5 of every 1,000 infants born; the rate of injury is lower in smaller infants (under 6 pounds) and increases as the size of the infant increases, especially in babies who weigh 9 pounds or more.
What is a Brachial Plexus Injury?
The brachial plexus is a bundle of nerves that runs from the neck through the shoulder to the arm. Although injury can happen anytime, most brachial plexus injuries occur during birth when the infant's shoulder becomes wedged in the birth canal. This event, called shoulder dystocia, can stretch the brachial plexus, damaging the nerves. The delivery becomes an emergency situation, and additional maneuvers are required to deliver the infant. Injury also may occur without shoulder dystocia if the labor is long, the infant is large, the mother develops gestational diabetes, the delivery requires external assistance (such as forceps), or if a breech birth (buttocks- or feet-first rather than head-first) occurs.
Possible Causes
Erb's or Klumpke's Palsies result from 4 types of brachial plexus injuries:
- Neuropraxia occurs when 1 or more of the nerves are stretched and damaged, but not torn. It is the most common type of injury to the nerves of the brachial plexus, and may heal spontaneously.
- Neuroma results from a torn nerve that heals, but scar tissue develops. The scar tissue puts pressure on the injured nerve and prevents signals from being transmitted between nerves and muscles. Neuroma injuries require treatment to heal.
- Rupture describes a torn nerve, but the tear is not at the site where the nerve attaches to the spine. Surgery will be required, and the muscles may continue to weaken if physical therapy treatment does not occur following surgery.
- Avulsion is the most severe type of injury, in which the nerve is torn from the spine. The size and growth of the arm or hand may be affected, and damage may be present for life.
Signs and Symptoms
The signs and symptoms of brachial plexus injury vary, depending upon which nerves are damaged and the extent of the damage. Major damage may result in a limp or paralyzed arm. The arm muscles are weak and lack feeling or sensation.
In Erb's Palsy, the signs may be a stiff arm that is rotated inward with the wrist fully bent and fingers extended. This position is often called the "waiter's tip" because it resembles a food server holding the hand discreetly for a tip.
If other nerves are damaged, as in Klumpke's Palsy, the posture of the arm will be different. Sometimes the fingers and hand can move even when the arm has limited movement. The amount of pain that is present also is dependent upon the extent of the nerve damage.
How Is It Diagnosed?
Brachial plexus injuries are often apparent at birth because the infant's arm is limp or unusually stiff. Diagnosis of the injury requires a careful neurological examination by a specialist to determine which nerves have been affected, and the severity of the injury. Usually, the examination will include physical observation of the arm as well as some special tests, such as an electromyogram (EMG) that reveals the extent of muscle damage caused by the nerve injury. A nerve conduction study (NCS) may be used to determine how far signals are transmitted along the nerves. Other scans may be required to assess the damage to the nerves.
Some children's hospitals offer a team approach in diagnosing and treating children with brachial plexus injuries. The specialists on the team might include physicians, orthopedic surgeons, and physical therapists. Surgery may be necessary if the nerve damage is too extensive for recovery with therapy alone. Physical therapy will likely be a part of the treatment plan, whether or not the child has surgery. Sensory re-education may be included if the brain forgets how the arm and hand should function during the time the nerve is regrowing or healing. Seeking treatment as early as possible, and seeking care by experts in brachial plexus injury can make a big difference in helping a child gain full use of their arm.
How Can a Physical Therapist Help?
A physical therapist is an important family treatment partner for any child diagnosed with a brachial plexus injury. Physical therapy should begin as soon as possible after diagnosis or surgery, and before joint or muscle tightness has developed. Physical therapists will:
- Identify muscle weakness and work with each child to keep muscles flexible and strong.
- Help reduce or prevent muscle or joint contractures (tightening) and deformities.
- Encourage movement and function.
Even when surgery is not required, therapy may need to continue for weeks and months as the nerves grow again or recover from damage. Children with Erb's Palsy will usually recover by 6 months of age, but other palsies may require longer treatment. Each treatment plan is designed to meet the child's needs using a family-centered approach to care.
Evaluation. Your child's physical therapist will perform an evaluation that includes a detailed birth and developmental history. Your child’s physical therapist will perform specific tests to determine arm function, such as getting the child to bring the hands together, grasp a toy, or use the arm for support or for crawling. The physical therapist will test arm sensation to determine whether some or all feeling has been lost, and educate the family about protecting the child from injuries when the child may not be able to feel pain. Physical therapists know the importance of addressing the child’s needs with a team approach, review all health care assessments, and send the child for further evaluation, if needed.
Treatment. Physical therapists work with children with brachial plexus injury to prevent or reduce joint contractures, maintain or improve muscle strength, adapt toys or activities to promote movement and play, and increase daily activities to encourage participation—first in the family, and later, in the community. Treatments may include:
- Education on holding, carrying, and playing with the baby. Your physical therapist will make suggestions for positioning, so that your baby's arm will not be left hanging when the baby is being held or carried. Your physical therapist will provide ideas for positioning the baby on the back or stomach for play without injury to the arm.
- Prevention of injury. Your physical therapist will explain the possible injuries that could occur without the baby crying, since the baby cannot perceive pain if sensation is limited in the arm.
- Passive and active stretching. Your physical therapist will assist you and your child in performing gentle stretches to increase joint flexibility (range of motion), and prevent or delay contractures (tightening) in the arm.
- Improving strength. Your physical therapist will teach you and your child exercises and play activities to maintain or increase arm strength. Your physical therapist will identify games and fun tasks that promote strength without asking the baby to work too hard. As your child improves and grows, your physical therapist will identify new games and activities that will continue to strengthen the arm and hand.
- Use of modalities. Your physical therapist might use a variety of intervention techniques (modalities) to improve muscle function and movement. Electrical stimulation can be applied to gently simulate the nerve signal to the muscle and keep the muscle tissue functional. Flexible tape can be applied over specific muscle areas to ease muscle contraction. Constraint-induced movement therapy (CIMT) may be applied to the nonaffected arm to encourage use of the affected arm. Repetitive training of the affected arm is encouraged, using age-appropriate tasks, such as finger painting, building a tower, or picking up and eating small bites of food. Your physical therapist will collaborate with other health professionals to recommend the best treatment techniques for your child.
- Improving developmental skills. Your physical therapist will help your child learn to master motor skills, like putting the child’s weight on the injured arm, sitting up with arm support, and crawling. Your physical therapist will provide an individualized plan of care that is appropriate based on your child’s needs.
- Fostering physical fitness. Your physical therapist will help you determine the exercises, diet, and community involvement that will promote good health throughout childhood. Your physical therapist will continue to work with you and your child to determine any adaptations that may be needed, so that your child can participate fully in family life and in society.
Therapy may be provided in the home or at another location, such as a hospital, community center, school, or a physical therapy outpatient clinic. Depending upon the severity of the brachial plexus injury, the child's needs may continue and vary greatly as the child ages. Your physical therapist will work with other health care professionals, eg, occupational therapists and physicians, to address all your child's needs as treatment priorities shift.