Question

Ms. Addams is at the oral surgeon to have a simple procedure performed. The surgeon
injected a local anesthetic in the region where the procedure was to occur. After the surgery, Ms.
Addams had the customary numbness associated with the anesthesia. However, the next day,
despite the return of sensation to the area, Ms. Addams found she could not control the blinking
of her left eye and the eye was constantly tearing. Also, the left corner of her mouth lost vertical
dimension (sagged). Fearing a stroke, Ms. Addams reported to the ER where it was determined
that her symptoms were the result of trauma to one of her cranial nerves during the injection of
local anesthetic.

Answer the following questions:

1. What is the Cranial Nerve Damaged?

2. Function of This Nerve

3. How does the cranial nerves damage relate to the patients symptoms?

Answer 1

1. the cranial nerve which is damaged is facial nerve or cranial nerve VII.

2. The facial nerve has mainly motor supply to the muscles of facial expression. It also has sensory innervation to the skin behind the ear, it carries taste sensation from the anterior two-thirds of the tongue via the chordae tympani nerve. it has autonomic innervation to submandibular salivary glands and lacrimal glands.

muscles supplied by facial nerve involve

• stapedius muscle in the ear
• orbicularis oculi
• frontalis
• buccinator
• posterior belly of digastric
• orbicularis oris
• occipitalis
• platysma
• other muscles of facial expression

3. blinking of left eye is affected when there is paralysis of orbicularis oculi

tearing of left eye- facial nerve has parasympathetic innervation to the lacrimal glands. So when there is damage to the facial nerve, lacrimation should be is reduced. But because of the motor paralysis around the eye, the teardrop is not evenly distributed and may present as constant tearing.

sagging of left corner of the mouth- due to paralysis of muscles of facial expression