Erb palsy, also known as brachial plexus birth palsy, is a form of obstetric brachial plexus injury as a result of complications during delivery.
The most common cause is due to excessive lateral traction or stretching of the fetal head and neck in opposite directions during delivery, usually associated with shoulder dystocia. The brachial plexus can be compressed causing stretching or tearing when the infant's head has deviated away from the axial plane of the fetal body.
Symptoms of Erb palsy include:
- loss of motor and/or sensory function over the lateral proximal upper arm
- paralysis of hemidiaphragm
- numbness of the arm due to nerve damage
- infant unable to move upper or lower arm and/or hand from the shoulder
- the arm is limp, bent at the elbow and held against the body (waiter's tip)
- partial or complete paralysis
- impaired muscular, nervous, and/or circulatory development
The injury is most often where nerve roots form the trunk of the brachial plexus. It is caused by a lesion at Erb point where the fifth and sixth cervical nerves unite to form the upper trunk of the brachial plexus. The severity of the injury can range from minimal to intermediary to severe which can be permanent.
Two potentially harmful forces act on the brachial plexus during delivery - clinicians can underestimate the force they apply during downward traction and the naturally expulsive force of the uterus can have a major effect.
Treatment and prognosis
While most cases of Erb palsy are self resolving, the treatment for Erb palsy primarily involves physiotherapy.
Other less common treatment modalities with limited evidence include surgical reconstruction in severe plexopathies and the use of botulinum toxin injections.