Injuries to Cranial Nerves

Question 1

An injury to CN XII would cause what?

Answer 1

Periphal lesion –> protruded tongue deviates toward side of injury due to paralyis of tongue muscles

Question 1

What are symptoms of Bell’s palsy?

Answer 1

• Facial muscle paralysis
• Cannot close eyelids (orbicularis oculi)
• Angle of mouth droops (paralysis of m.’s around mouth)
• Forehead does not wrinkle (frontalis)

Question 1

An injury to CN IX would result in what?

Answer 1

• Dysphagia
• Dysarthria
• Changes in blood pressure (chemoreceptors in carotid body, barorecptors in carotid sinus)
• Loss of taste sensation from posterior 1/3 of tongue

Question 2

An injury to CN VI would cause what?

Answer 2

Abducent nerve pasly characterized by:

• Horizontal diplopia (double vision)
• Impaired eye abduction
• A tendency for the eye to turn medially (due to unopposed action of medial rectus m.)

Question 2

An injury to CN V2 would cause what?

Answer 2

Anesthesia of maxillary region

Trigeminal neuralgia / Tic douloureux (intermittent excruciating pain)

Question 2

Injury to CN VII distal to the geniculate ganglion results in what?

Answer 2

• Facial muscle paralysis
• Loss of taste (anterior 2/3rds of tongue)
• Loss of salivation from sublingual and submandibular glands
• Hyperacusis (due to paralysis of stapedius m.)

Question 3

An injury to CN VIII would cause what?

Answer 3

Hearing impairment or loss

Vertigo (dizziness)

Question 5

What would cause an injury to CN II?

Answer 5

Eyeball trauma

Question 6

Bell’s palsy is caused by damage to what area?

Answer 6

Injury in region of parotid gland (i.e. distal to stylomastoid foramen)

Injury to CN VII - Facial

Question 7

What is hyperacusis?

Answer 7

Condition characterized by an over-sensitivity to certain frequency and volume ranges of sound caused by damage to CN VII distal to the geniculalte ganglion.

Question 8

Injury to CN VII distal to the stylomastoid foramen results in what?

Answer 8

Facial muscle paralysis

Question 10

What would cause an injury to CN I?

Answer 10

Fracture of the cribiform plate

Question 10

An injury to CN V3 would cause what?

Answer 10

Sensory: Anesthesia to mandibular region

Motor: difficulty chewing

Question 11

What would cause an injury to CN V2?

Answer 11

Inflammation

Question 12

What would cause an injury to CN III?

Answer 12

Cavernous sinus injury

Aneurysm of posterior cerebral or superior cerebellar arteries

Question 13

A drooping eyelid (ptosis) would indicate an injury to which muscle and nerve?

Answer 13

Levator palpebrae muscle

CN III

Question 14

An injury to CN I would result in what?

Answer 14

Anosmia (loss of sense of smell)

Question 15

An injury to CN IV would result in what?

Answer 15

An inability to look down when eye is adducted (diplopia)

Question 15

An injury to the chorda tympani nerve would cause what?

Answer 15

Loss of taste sensation from anterior 2/3rds of tongue

Question 17

An injury to CN III would cause what?

Answer 17

Complete oculomotor nerve palsy characterized by:

• Ptosis (eyelid droops due to paralyis of levator palpebrae m.)
• A resting eye position that is down and out
• A pupil that is fixed and dilated (mydriasis)

Question 18

Injury to CN X would result in what?

Answer 18

• Sagging soft palate
• Difficulty coughing, clearing throat, swallowing (reccurrent laryngeal n. injury)
• Dysphagia (due to paralysis of muscles in soft palate)

Question 19

What is dysphagia?

Answer 19

Difficulty swallowing

Question 20

Injury to CN VII proximal to branching off of chorda tympani results in what?

Answer 20

• Facial muscle paralysis
• Loss of taste (anterior 2/3rds of tongue)
• Loss of salivation from sublingual and submandibular glands

Question 21

What would cause an injury to CN IX?

Answer 21

Neck laceration

Question 22

What is dysarthria?

Answer 22

Speech difficulty

Question 24

What would cause an injury to CN IV?

Answer 24

Cavernous sinus injury

Question 26

An injury to CN II would cause what?

Answer 26

Anopsias (visual field defects)

Question 26

An injury to CN V1 would result in what?

Answer 26

Anesthesia in ophthalmic region (loss of pain and touch sensation)

Question 27

What is mydriasis?

Answer 27

Pupil dilation due to paralysis of sphincter pupillae muscle and unopposed action of dilaor pupillae muscle.

Question 29

The stapedius muscle is innervated by what nerve?

Answer 29

CN VII - Facial

Question 31

What would cause an injury to CN XI?

Answer 31

Neck laceration

Question 32

What would cause an injury to CN V1?

Answer 32

Inflammation

Question 33

Injury to CN VII with involvement of the greater petrosal nerve results in what?

Answer 33

• Facial muscle paralysis
• Loss of taste (anterior 2/3rds of tongue)
• Loss of salivation from sublingual and submandibular glands
• Hyperacusis (due to paralysis of stapedius m.)
• Loss of taste (palate)
• Loss of lacrimation

Question 34

What would cause an injury to CN VIII?

Answer 34

A tumor

Question 35

What would cause an injury to CN V3?

Answer 35

Inflammation

Question 36

An injury to CN XI would result in what?

Answer 36

• Weakness in turning head to opposite side (sternocleidomastoid)
• Weakness in shrugging shoulders (trapezius)

Question 37

What would cause an injury to CN XII?

Answer 37

Neck laceration

Question 38

What would cause an injury to CN VI?

Answer 38

Cavernous sinus injury

Fracture of base of skull