Certified Neuroscience Registered Nurse (CNRN) Practice Exam

What is the most common cause of Erb's palsy?

1. Trauma from heavy lifting

2. Dystocia during childbirth

3. Infection during pregnancy

4. Neuromuscular diseases

The correct answer is: Dystocia during childbirth

The most common cause of Erb's palsy is dystocia during childbirth. This condition occurs when there are complications in the delivery process, leading to excessive stretching or pulling of the infant's shoulder, particularly during a difficult labor. Such complications can result in brachial plexus injury, which is the underlying issue in Erb's palsy, characterized by weakness or paralysis of the arm on the affected side. In the context of childbirth, the brachial plexus consists of nerves that control muscle movements and sensations in the arm and hand. When an infant is delivered with shoulder dystocia, the nerves can be damaged, resulting in the characteristic signs of Erb's palsy, such as the inability to move the arm or weakness in the shoulder area. Other potential causes, such as trauma from heavy lifting or infections and neuromuscular diseases, are less relevant in this specific context. Heavy lifting might cause injuries in adults but does not pertain to Erb's palsy in infants. Infections during pregnancy could complicate neonatal outcomes but are not a direct cause of Erb's palsy. Similarly, neuromuscular diseases might affect muscle tone and strength but do not lead to the specific shoulder injury resulting from childbirth complications.