Damage to which nerve is associated with facial paralysis in the newborn when injured pre- or perinatally?

• A. Trigeminal nerve
• B. Glossopharyngeal nerve
• C. Seventh cranial nerve
• D. Vagus nerve

Answer: (C)

The facial nerve, which is the seventh cranial nerve, controls the muscles of facial expression. When a newborn’s face is stretched or compressed during delivery, this nerve can be injured, leading to facial paralysis on the affected side. This presents as an inability to close the eye, drooping of the mouth, and asymmetrical facial movements, often noticed when the baby tries to smile or blink. This type of birth-related facial nerve palsy is common and usually improves as the nerve heals over weeks to months.

The other nerves described have different roles: the trigeminal nerve mainly handles facial sensation and muscles of mastication, not causing a full facial paralysis; the glossopharyngeal and vagus nerves are involved in swallowing and voice/palate function, not the facial movements.