Sun28November0628PM 43

A 70-year-old man presents for surgery.

He has had a stroke in the past and has residual neurological deficit. The cranial nerves are clinically examined. It is found that he is unable to rotate his head to the left side against resistance. He also has wasting of the tongue on the right side. There are no abnormal sensory signs.

Which one of the following options is the most likely reason for the clinical findings?

(Please select 1 option)

Damage to hypoglossal (XII) and spinal accessory (XI) nerves This is the correct answer

Damage to spinal accessory (XI) nerve

Damage to glossopharyngeal (IX) and hypoglossal (XII) nerves

Damage to hypoglossal (XII) and vagus nerves (X) Incorrect answer selected

Damage to glossopharyngeal (IX) and vagus (X) nerves

Explanation

XI cranial nerve arises from the upper five cervical segments of the spinal cord. They join some smaller branches and exit the skull via the jugular foramen. The accessory root provides the motor supply to the sternomastoid and trapezius muscles. Hypoglossal nerve provides motor supply to all the tongue muscles except palatoglossus.

Damage to the spinal accessory nerve will cause an inability to shrug the shoulder on the affected side and rotate the head to the side against resistance. This is due to the weakness of the trapezius and sternomastoid muscles.

Damage to the hypoglossal nerve causes wasting of the tongue and inability to move from side to side.

The glossopharyngeal nerve provides motor supply to the stylopharyngeus. It also carries sensory fibres of taste from the posterior 1/3 of the tongue and carotid sinus, carotid body, pharynx and middle ear.

The vagus nerve provides motor supply to larynx, pharynx and palate; parasympathetic innervation to the heart, lung and gut, sensory fibres from the epiglottis and valleculae.

Answer Statistics

1

79%

2

4%

3

16%

4

2%

5

2%

Times answered: 299