The facial nerve is the 7th cranial nerve and is responsible for facial expression, such as smiling and eye closure. The facial nerve forms at the brainstem then courses through the temporal bone of the skull, exits the bone below the ear then branches into many smaller branches in front of the ear into the muscles of facial expression. When there is a problem anywhere along the path of the facial nerve, facial paralysis can result.
In younger patients, the cause of facial paralysis can occur for many reasons. The two main types of facial nerve paralysis include congenital facial paralysis which is by definition present at birth. This can occur due in our patients with craniofacial abnormalities such as hemifacial microsomia population as well as in Mobius syndrome. Mobius syndrome is a constellation of facial findings that includes absence of facial nerve development and thus, facial paralysis, as well as other cranial nerve abnormalities. The second type of facial paralysis is the acquired form where the child suffers facial nerve injury at the time of birth due to a traumatic birth process or time in the birth canal.