Erb's Palsy is a birth injury in which nerves at the base of the baby’s neck are damaged during delivery resulting in full or partial paralysis in the baby’s arm. Children with Erb’s Palsy (or Erb-Duchenne Palsy) will have some level of physical disability and paralysis in the affected arm. The most severe cases of Erb’s Palsy can involve complete paralysis from the shoulder down, but most cases involve only moderate immobility.
Erb’s Palsy is an injury during childbirth, not a disease. It results when a baby’s brachial plexus nerves are torn during a difficult vaginal delivery. Like other birth injuries, Erb’s Palsy can be prevented with proper obstetric care. OB/GYNs should recognize the risks factors for nerve damage and Erb’s Palsy and take preventive measures.Medical Definition of Erb's Palsy
The brachial plexus is cluster of nerves in the shoulder area which connects the neck to the arm. Erb's Palsy is defined as arm paralysis caused by injury to a specific merger point of 2 nerve roots (know as “Erb’s point) in the brachial plexus. Erb’s Palsy can be distinguished from other types of brachial plexus injuries (such as Klumpke's Palsy) based on the location of the nerve injury. Erb’s Palsy specifically affects the upper two of the five brachial plexus nerves (C5&C6) and often does not prevent lower arm movements such as the wiggling of fingers.
Klumpke’s Palsy is similar but less common and it happens when the nerve damage occurs in a different junction point in the brachial plexus. Klumpke’s Palsy involves injury to the lower nerve junctions (the C8 and T1 nerve roots).
The brachial plexus is the most important set of nerves located within the arm, and their role is to give movement, flexibility, and feeling to the arm, hand, and fingers. These nerves consist of thousands of fibers which carry electrical signals back and forth between the brain and the muscles of the arm and hand. When injured, normal nerve impulses are impaired and the spinal cord is unable to send messages to the arm, hand, wrist, and/or fingers as they normally would.Presentation and Characteristics of Erb’s Palsy
The singular characteristic of Erb’s Palsy is immobility, weakness, or paralysis in the arm. Paralysis is from the shoulder down and can be complete or only partial. Feeling and sensation is usually diminished in the arm. This lack of sensation, combined with the paralysis, usually leads to muscular atrophy in the biceps, deltoid, and other arm muscles.
In moderate to severe cases of Erb’s Palsy, the affected arm will often be noticeably abnormal in physical appearance. The arm will hang awkwardly and rotate inward. The atrophy of the biceps causes the wrist to be pulled or flexed instead of straight. This is sometimes described as “waiter’s tip arm” because it looks similar to a waiter when receiving a tip. The impacted arm will often have stunted growth and be noticeably smaller than the other arm.Categories of Erb’s Palsy
Depending on the severity of the injury, Erb's Palsy is typically classified into four categories, which are characterized as follows:
- Neuropraxia - As the mildest form of Erb's Palsy, the brachial plexus is stretched or shocked but does not tear. This is the easiest form to deal with, and also the most common. Although it typically heals completely within three months, it can still send burning pain and your child may experience some intense discomfort during this time.
- Neuroma - This is a consequence of more serious stretching, in which some nerve fibers have also been damaged. As a result, this can lead to scarring and discomfort, and long-term recovery is usually partial. It is accompanied by the same burning sensations as neuropraxia and should heal - but not always fully. Physical therapy and surgery typically help with the recovery.
- Rupture - This is a stretch injury from nerve tearing, and requires surgery to repair the nerve - it can't heal on its own. This is usually done by a physician who splices and grafts a healthy nerve from another part of the body, which will return feeling, flexibility and support to the affected area - but there will be challenges even after treatment.
- Avulsions - As the most severe form of Erb's Palsy, the nerve has been totally torn from the spinal cord. Your child's arm will be completely motionless but may be able to regain its mobility after surgery. Some recovery is possible but typically only with surgical intervention.
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- Abzug, Joshua M., et al. "Loss of midline function in brachial plexus birth palsy patients." Journal of Pediatric Orthopaedics 39.3 (2019): e232-e235.