Deck 15: The Cranial Nerves and Trigeminal Nerve Blocks

Question 1

A 73-year-old woman visited her physician because she had noticed that the right side of her face was sagging downward. She first noticed the condition on waking up two mornings ago. Otherwise she felt very well. On examination the patient had a complete right-sided facial paralysis, the right lower eyelid was drooping, and the right angle of the mouth was sagging. A diagnosis of Bell's palsy was made.

-Further examination of this patient demonstrated the following signs and symptoms except which?

A) Tears tended to flow easily over the right lower eyelid.
B) Saliva dribbled from the right corner of her mouth.
C) The patient was unable to close her right eye completely.
D) The patient was unable to expose the teeth fully on the right side of her mouth.
E) The muscles on the right side of her forehead worked perfectly normally when she was asked to raise her right eyebrow.

Answer 1

The muscles on the right side of her forehead worked perfectly normally when she was asked to raise her right eyebrow.

Question 2

A 17-year-old boy was seen in the emergency department after receiving a stab wound at the front of the neck. The knife entrance wound was located on the left side of the neck just lateral to the tip of the greater cornu of the hyoid bone. Dur- ing the physical examination the patient was asked to protrude his tongue, which deviated to the left.

-The following statements would explain the physical signs in this patient except which?

A) The genioglossus muscles are responsible for protruding the tongue.
B) The genioglossus muscle is supplied by the glossopharyngeal nerve.
C) Paralysis of the left genioglossus muscle permitted the right genioglossus to pull the tongue forward and turned the tip to the left side.
D) The hypoglossal nerve descends in the neck between the internal carotid artery and the internal jugular vein.
E) At about the level of the tip of the greater cornu of the hyoid bone the hypoglossal nerve turns forward and crosses the internal and external carotid arteries and the lingual artery to enter the tongue.
F) The point of the knife blade severed the left hypoglossal nerve.

Answer 2

The genioglossus muscle is supplied by the glossopharyngeal nerve.

Question 3

A 43-year-old woman was seen in the emergency department with a large abscess in the middle of the right posterior triangle of the neck. The abscess was red, hot, and fluctuant. The abscess showed evidence that it was pointing and about to rupture. The physician decided to incise the abscess and insert a drain. The patient returned to the department for the dressings to be changed 5 days later. She stated that she felt much better and that her neck was no longer painful. However, there was one thing that she could not understand. She could no longer raise her right hand above her head to brush her hair.

-The following statements explain the signs and symptoms in this case, suggesting that the spinal part of the accessory nerve had been incised, except which?

A) To raise the hand above the head, it is necessary for the trapezius muscle, assisted by the serratus anterior, to contract and rotate the scapula so that the glenoid cavity faces upward.
B) The trapezius muscle is innervated by the spinal part of the accessory nerve.
C) As the spinal part of the accessory nerve crosses the posterior triangle of the neck, it is deeply placed, being covered by the skin, the superficial fascia, the investing layer of deep cervical fascia, and the levator scapulae muscle.
D) The surface marking of the spinal part of the accessory nerve is as follows: Bisect at right angles a line joining the angle of the jaw to the tip of the mastoid process. Continue the second line downward and backward across the posterior triangle.
E) The knife opening the abscess had cut the accessory nerve.

Answer 3

As the spinal part of the accessory nerve crosses the posterior triangle of the neck, it is deeply placed, being covered by the skin, the superficial fascia, the investing layer of deep cervical fascia, and the levator scapulae muscle.

Question 4

A 35-year-old woman had a partial thyroidectomy for the treatment of thyrotoxicosis. During the operation a ligature slipped off the right superior thyroid artery. To stop the hemorrhage, the surgeon blindly grabbed for the artery with artery forceps. The operation was completed without further incident. The following morning the patient spoke with a husky voice.

-The following statements about this patient would explain the husky voice except which?

A) Laryngoscopic examination revealed that the right vocal cord was slack, causing the huskiness of the voice.
B) The vocal cord is tensed by the contraction of the cricothyroid muscle.
C) The cricothyroid muscle tilts back the cricoid cartilage and pulls forward the thyroid cartilage.
D) The cricothyroid muscle is innervated by the recurrent laryngeal nerve.
E) The superior thyroid artery is closely related to the external laryngeal nerve.

Question 5

A 43-year-old woman visited her physician complaining of severe intermittent pain on the right side of her face. The pain was precipitated by exposing the right side of her face to a draft of cold air. The pain was stabbing in nature and lasted about 12 hours before finally disappearing. When asked to point out on her face the area where the pain was experienced, the patient mapped out the skin area over the right side of the lower jaw extending backward and upward over the side of the head to the vertex.

-The following signs and symptoms in this patient strongly suggest a diagnosis of trigeminal neuralgia except which?

A) The skin area where the patient experienced the pain was innervated by the mandibular division of the trigeminal nerve.
B) The stabbing nature of the pain is characteristic of the disease.
C) The trigger mechanism, stimulation of an area that received its sensory innervation from the trigeminal nerve, is characteristic of trigeminal neuralgia.
D) Examination of the actions of the masseter and the temporalis muscles showed evidence of weakness on the right side.
E) The patient experienced hyperesthesia in the distribution of the right auriculotemporal nerve.

Question 6

A 10-year-old boy was playing darts with his friends. He bent down to pick up a fallen dart when another dart fell from the dart board and hit him on the side of his face. On examination in the emergency department a small skin wound was found over the right parotid salivary gland. Then, 6 months later, the boy's mother noticed that before mealtimes the boy began to sweat profusely on the facial skin close to the healed dart wound.

-The following statements can explain this phenomenon except which?

A) The point of the dart had entered the parotid salivary gland and damaged the parasympathetic secretomotor fibers to the gland.
B) The secretomotor fibers to the parotid gland arise in the otic ganglion.
C) The preganglionic parasympathetic fibers originate in the superior salivatory nucleus of the facial nerve.
D) The skin over the parotid salivary gland is innervated by the great auricular nerve, which was also damaged by the dart.
E) On regeneration of the damaged nerves some of the parasympathetic nerves to the parotid salivary gland had crossed over and joined the sympathetic secretomotor nerves to the sweat glands in the distal end of the great auricular nerve.
F) The patient has Frey's syndrome.

Question 7

A 31-year-old woman fell off her bicycle and lacerated the skin of her forehead just above the left eyebrow.
-What is the sensory innervation of the skin of the forehead? Where may these nerves be blocked?

Question 8

A 27-year-old man was involved in a motorcycle accident and was seen in the emergency department with extensive lacerations of the right ear. It was decided to suture the skin lesions under local anesthesia.
-How would you anesthetize the ear?

Question 9

A 63-year-old woman visited her physician with a swelling over the parotid gland on the right side. She stated that she had first noticed the swelling 3 months previously, and since that time it had rapidly increased in size. Recently, she had noticed that the right side of her face "felt weak" and she could no longer whistle for her dog. On examination, a hard swelling deeply attached to the parotid gland was found. On testing the facial muscles, it was found that the muscles on the right side were weaker than those on the left side.
-What is the connection between the parotid swelling and the right-sided facial weakness?

Question 10

On examination, a patient is found to have a bitemporal hemianopia. An enlargement of which anatomic structure is likely to cause this condition?

Question 11

A patient is suspected of having a lesion of the glossopharyngeal nerve. How would you test the integrity of this cranial nerve?

Question 12

A47-year-old woman is seen by a neurologist because of trouble reading the newspaper. She said that the print starts to tilt and she begins to see double. She also stated that she has difficulty walking down steps because she cannot easily look downward with her right eye. On physical examination, the patient was found to have weakness of the movement of the right eye, both downward and laterally. Using your knowledge of anatomy, explain the signs and symptoms.