Cranial nerves ( 7-12)

Question 1

Cranial nerve VII

Answer 1

Facial nerve

Question 2

Function of cranial nerve VII

Answer 2

1. supplies the muscles of facial expression

2. taste from the anterior 2/3 of the tongue

Question 3

Upper motor neuron lesion of CN VII

Answer 3

1. weakness of the lower part of the face

- sparing the forehead and eye closure

Question 4

Lower motor neuron lesion of CN VII

Answer 4

1. weakness of all facial muscles on the affected side

Question 5

Causes of upper motor neuron lesion of CN VII

Answer 5

1. Stroke
2. Multiple sclerosis
3. Brain tumor

Question 6

Causes of lower motor neuron lesion of CN VII

Answer 6

1. most commonly causes by bell’s palsy
2. Herpes zoster infection
3. Sarcoidosis
4. Guillian Barre syndrome

Question 7

Bell’s palsy

Answer 7

1. acute
2. unilateral
3. lower motor neurone facial weakness
4. pain or discomfort behind the ipsilateral ear
5. full spontaneous recovery occurs in 90% of the cases but may take 9 months
6. oral prednisolone increases likelihood of full recovery
7. Eye protection is important as weakness of eyelid closure can cause corneal abrasions

Question 8

Cranial nerve VII

Answer 8

1. carries auditory fibres from cochlea

2. carries vestibular fibres from semicircular canals for balance

Question 9

causes of Cranial nerve VII palsy

Answer 9

1. Stroke
2. Multiple sclerosis
3. Trauma
4. Acoustic neuroma

Question 10

Cranial nerve VII palsy

Answer 10

1. sensorineuronal deafness
2. tinnitus
3. vertigo
4. nystagmus

Question 11

Cranial nerve IX

Answer 11

Glassopharyngeal nerve

Question 12

Cranial nerve IX function

Answer 12

1. sensation to the pharynx

2. taste to the posterior third of the tongue

Question 13

Cranial nerve X

Answer 13

Vagus nerve

Question 14

Cranial nerve X function

Answer 14

1. motor supply to the pharynx, larynx and upper oesophagus

Question 15

Bulbar palsy

Answer 15

1. both CNIX and CNX are affected togather
   clinical features reflect impairment of pharyngeal control and swallowing
2. Bulbar palsy (lower motor neurone lesion)
   - nasal speech
   - dysphagia with nasal regurgitation
   - ‘weak’ bovine cough
   - wasted tongue
   - absent gag reflex

Question 16

Pseudo bulbar palsy ( upper motor neurone lesion)

Answer 16

1. spastic dysarthia - 
a type of motor speech disorder affecting speech articulation, caused by lesions of the corticobulbar tracts
2. dysphagia with choking
3. spastic immobile tongue
4. brisk jaw jerk
5. brisk gag reflex

Question 17

Cranial nerve XI

Answer 17

Accessory nerve

Question 18

Cranial nerve XI function

Answer 18

1. supplies the trapezius and sternocleidomastoid muscle

Question 19

Cranial nerve XI palsy

Answer 19

1. muscle weakness
2. impaired shoulder shrug
3. impaired head rotation

Question 20

Cranial nerve XII

Answer 20

Hypoglossal nerve

Question 21

Cranial nerve XII function

Answer 21

1. motor supply to the tongue

Question 22

Cranial nerve XII palsy

Answer 22

1. unilateral weakness, wasting and fasciculation of the tongue
2. upon protrusion of the tongue there is deviation towards the affected side

Question 23

Cause of Cranial nerve XII palsy

Answer 23

1. malignant meningitis

2. base of skull fracture