A 24-year-old woman is transported to the emergency department by ambulance following a motor vehicle accident. She is noted to have facial lacerations on the left and a small amount of blood in the external auditory canal. If the facial nerve is damaged during its course through the external auditory meatus, which of the following senses will be compromised?
C) Muscles of facial expression
The facial nerve enters the internal auditory meatus, courses through the facial canal, and then exits the temporal bone through the external auditory meatus. While the facial nerve has sensory, motor, and parasympathetic functions, the specific nerve fibers exiting the external auditory meatus are responsible for innervating the muscles of facial expression.
Answer choice A: Facial sensation, is incorrect. The trigeminal nerve is responsible for facial sensation.
Answer choice B: Lacrimal gland secretion, is incorrect. Facial nerve functions such as lacrimal gland secretion are associated with the geniculate ganglion in the facial canal.
Answer choice D: Taste sensation to anterior 2/3 of tongue, is incorrect. Facial nerve functions such as taste to the anterior 2/3 of the tongue are associated with the geniculate ganglion in the facial canal.
Answer choice E: Taste sensation to posterior 1/3 of tongue, is incorrect. The glossopharyngeal nerve is responsible for taste sensation from the posterior 1/3 of the tongue.
Key Learning Point
The facial nerve enters the internal auditory meatus, courses through the facial canal, and then exits the temporal bone through the external auditory meatus. The nerve fibers exiting the external auditory meatus are responsible for innervating the muscles of facial expression.
