Brachial plexus palsy is an injury to a group of nerves called the brachial plexus that run from the spinal cord between the neck and shoulders. This complex bundle of nerves is responsible for movement and feeling from the shoulder to the fingers.
Brachial plexus injuries are caused by trauma, inflammation, and tumors and occur in both children and adults. The most common occurrence of brachial plexus injury in children is due to trauma sustained in the birth process. This condition is also called obstetric brachial plexus injury (OBPI) or birth brachial plexus injury (BBPI).
Brachial plexus palsy most often occurs during a difficult labor when a baby’s shoulders are impacted, causing great strain on the nerves as the neck and shoulders are pushed in opposition. The resulting nerve injury can cause weakness and loss of motion to one side of the baby’s shoulder, arm, wrist, and fingers. One to two in 1,000 births result in a brachial plexus injury, with severity ranging from partial impediment to complete paralysis.
Signs of a brachial plexus injury usually appear shortly after birth. They include:
- A lack of the Moro reflex, also known as the infant startle reaction, on one side.
- A loss of function on the affected arm/shoulder, resulting in the arm tilting inward towards the body.
- The head tilting to the opposite side of the injury.