(A) Ectropion resulting from dysfunction of the orbicularis muscle
(B) Ectropion resulting from dysfunction of the trigeminal (V) nerve
(C) Entropion resulting from dysfunction of the facial (VII) nerve
(D) Ptosis resulting from dysfunction of the oculomotor (III) nerve
(E) Ptosis resulting from dysfunction of the levator muscle

The correct response is Option A.

Bell’s palsy, or unilateral idiopathic facial nerve paralysis, is the most common cause of facial paralysis, occurring in approximately 80% of symptomatic patients. Diagnosing this condition involves excluding other causes, such as trauma, stroke, and tumor; as a result, thorough evaluation should be undertaken.

Patients with Bell’s palsy have dysfunction of the orbicularis oculi muscle, which is innervated by the zygomatic branches of the facial (VII) nerve. Ectropion, rather than entropion, is characteristic, and the patient is often unable to close the eye on the affected side.

The trigeminal (V) nerve is a sensory nerve that does not affect the muscle function of the eyelid.

Ptosis of the eyelids does not occur, because the levator muscle is innervated by the oculomotor (III) nerve and is thus uninvolved.

References
1. Anderson JE, ed. Grant’s Atlas of Anatomy. 8th ed. Baltimore, Md: Williams & Wilkins; 1983.
2. Carraway J. Correction of blepharoptosis. In: Achauer BM, Eriksson E, Guyuron B, et al, eds. Plastic Surgery: Indications, Operations and Outcomes. Saint Louis, Mo: Mosby - Year Book, Inc; 2000:2549-2561.

For each patient, select the nerve most likely to cause the findings (A-E).

(A) Acoustic nerve
(B) Auriculotemporal nerve
(C) Chorda tympani
(D) Great auricular nerve
(E) Tympanic nerve

Q1) A 62-year-old man has gustatory sweating three months after undergoing rhytidectomy.

Q2) A 56-year-old woman has persistent numbness in the right ear one year after undergoing deep-plane rhytidectomy.

The correct response for Question 1 is Option B and for Question 2 is Option D.

The 62-year-old man with gustatory sweating has Frey’s syndrome, which may occur following rhytidectomy or parotidectomy. This condition is caused by dysfunction of the auriculotemporal nerve, which is a branch of the mandibular division of the trigeminal nerve (V3). During surgery, the pathways of the auriculotemporal nerve become disrupted and then regenerate incorrectly, resulting in parasympathetic innervation of sympathetic nerve receptors. As a result, affected patients have facial flushing and sweating that occur with gustatory stimulation. Appropriate management includes injection of botulinum toxin (Botox) and operative placement of acellular dermal homograft (Alloderm) or a dermis-fascia-fat graft over the affected area to curb the symptoms.

The 56-year-old woman has persistent numbness of the right ear caused by injury to the great auricular nerve, which is derived from branches of cervical nerve roots C2-3 within the cervical plexus. The great auricular nerve crosses the sternocleidomastoid muscle 6.5 cm inferior to the tragus and provides sensation to the ear and postauricular region. If it is not identified prior to dissection, it can be injured easily because of its superficial location. It is the most commonly injured nerve during rhytidectomy, resulting in numbness of the ear.

The acoustic (VIII) nerve, also known as the vestibulocochlear nerve, divides into vestibular and cochlear branches near the lateral end of the internal acoustic meatus. The function of these branches is related to balance and hearing. This nerve is not encountered during dissection for rhytidectomy.

The chorda tympani is a branch of the facial (VII) nerve and is not injured in rhytidectomy. This nerve branch provides taste sensation to the anterior two-thirds of the tongue and parasympathetic secretory fibers to the submaxillary and sublingual glands.

The glossopharyngeal (IX) nerve provides taste sensation to the posterior third of the tongue and sensation to the mucous membranes of the pharynx and palatine tonsil. The tympanic branch of the glossopharyngeal nerve, also known as the nerve of Jacobson, provides sensation to the tympanic cavity and can cause referred pain to the ear in patients with carcinoma of the head and neck.

References
1. Laskawi R, Rohrbach S. Frey’s syndrome. Treatment with botulinum toxin. Curr Probl Dermatol. 2002;30:170-177.
2. Naumann M. Evidence-based medicine: botulinum toxin in focal hyperhidrosis. J Neurol. 2001;248:31-33.
3. Netter FH. Atlas of Human Anatomy. 3rd ed. New York, NY: Novartis Medical Education; 2003.
4. Sood S, Quraishi MS, Bradley PJ. Frey's syndrome and parotid surgery. Clin Otolaryngol. 1998;23:291-301.