Brachial plexus injury is a loss of movement or weakness of the arm. It occurs when the collection of nerves around the shoulder (called the brachial plexus) are damaged during birth.
The nerves of the brachial plexus can be injured during a difficult delivery. The injury may be caused by:
- The infant's head and neck pulling toward the side as the shoulders pass through the birth canal
- Pulling on the infant's shoulders during a head-first delivery
- Pressure on the baby's raised arms during a breech (feet-first) delivery
There are different forms of brachial plexus injury in an infant. The type depends on the amount of arm paralysis:
- Brachial plexus injuries usually affect only the upper arm.
- Erb's paralysis affects the upper and lower arm.
- Klumpke paralysis affects the hand. The infant may also have an eyelid droop on the opposite side.
The following factors increase the risk of brachial plexus injury:
- Breech delivery
- Larger-than-average newborn (such as an infant of a diabetic mother)
- Difficulty delivering the baby's shoulder after the head has already come out (called shoulder dystocia)
Brachial plexus injury is less common now that delivery techniques have improved. Cesarean delivery is used more often when there are concerns about a difficult delivery. Although a C-section reduces the risk of injury it does not prevent it, and the procedure carries other risks.
Brachial plexus injury may be confused with a condition called pseudoparalysis. This is when the infant has a fracture and is not moving the arm because of pain, but there is no nerve damage.
Symptoms can be seen right away or soon after birth. They may include:
- No movement in the newborn's upper or lower arm or hand
- Absent Moro reflex on the affected side
- Arm flexed (bent) at elbow and held against body
- Decreased grip on the affected side
Exams and Tests
A physical exam most often shows that the infant is not moving the upper or lower arm or hand. The affected arm may flop when the infant is rolled from side to side.
The Moro reflex is absent on the side with the brachial plexus or nerve injury.
The health care provider will examine the collarbone to look for a fracture. The infant may need to have an x-ray taken of the collarbone.
Gentle massage of the arm and range-of-motion exercises are recommended for mild cases. The infant may need to be evaluated by specialists if the damage is severe or the condition does not improve in the first few weeks.
Surgery may be considered if some strength has not returned to the affected muscles by the time the baby is 3 - 6 months old.
Most babies will fully recover within 3 to 6 months. Those who do not recover during this time have a poor outlook. In these cases there may be a separation of the nerve root from the spinal cord (avulsion).
It is not clear whether surgery to fix the nerve problem can help. Nerve grafts and nerve transfers are sometimes tried.
In cases of pseudoparalysis, the child will begin to use the affected arm as the fracture heals. Fractures in infants heal quickly and easily in most cases.
- Abnormal muscle contractions (contractures) or tightening of the muscles. These may be permanent.
- Permanent, partial, or total loss of function of the affected nerves, causing paralysis of the arm or arm weakness
When to Contact a Medical Professional
Call your health care provider if your newborn shows a lack of movement of either arm.
Taking measures to avoid a difficult delivery, whenever possible, reduces the risk of brachial plexus injury in newborn babies.
Klumpke paralysis; Erb-Duchenne paralysis; Erb's palsy; Brachial palsy
Fenichel GM. Trauma and vascular disorders. In: Fenichel GM, ed. Neonatal Neurology. 4th ed. Philadelphia, PA: Elsevier Churchill Livingstone; 2006:chap 5.
Pham CB, Kratz JR, Jelin AC, Gelfand AA. Child neurology: brachial plexus birth injury: what every neurologist needs to know. Neurology. 2011;77:695-697. PMID: 21844527 www.ncbi.nlm.nih.gov/pubmed/21844527.
Update Date 12/4/2013
Updated by: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.