Cranial Nerves - Signs of Damage

Question 1

Potential signs of damage to CN V - Trigeminal, Branch 3 - Mandibular (Sensory and Motor)

Answer 1

• Note weakness, asymmetry, tremors or fasiculations in jaw
• Weakness in jaw lateralisation and closure
• Loss of/weak mastication
• Jaw deviates to weak/paralysed side
• Flaccid soft palate
• Decreased hyolaryngeal excursion

Question 2

Potential signs of damage to CN II - Optic

Answer 2

• Blindness

Question 3

Potential signs of damage to CN IV - Trochlear

Answer 3

• Diplopia - double vision.
• Weakness of downward eye movement.
• Affected eye drifts upward.

Question 4

Potential signs of damage to CN I - Olfactory

Answer 4

• Anosmia - loss of sense of smell.

Question 5

Potential signs of damage to CN IX - Glossopharyngeal

Answer 5

• Weak cough reflex
• Weakness may be apparent on an instrumental exam
• Loss of taste and sensation (posterior 1/3 of tongue)
• May reduce gag bc sensation is reduced

Question 6

Potential signs of damage to CN VII - Vestibulocochlear

Answer 6

• Vertigo
• Nystagmus
• Hearing

Question 7

Potential signs of damage to CN XI - Accessory

Answer 7

• Difficulty turning head/shrugging shoulders

Question 8

Potential signs of damage to CN V - Trigeminal, Branch 1 - Ophthalmic and Branch 2 - Maxilliary (Sensory)

Answer 8

• Facial Anesthesia - numbness
• Loss of temperature/pain sensation
• Loss of sensation of superficial and deep structures
• Loss of sensation in anterior 2/3 of tongue

Question 9

Potential signs of damage to CN X - Vagus

Answer 9

• Loss of gag reflex
• Soft palate and uvula will deviate to non-damaged side
• Loss of cough reflex
• Loss of taste
• Hypernasality
• Dysphonia
• No variation to pitch
• Dysphagia
• Impaired laryngeal closure
• Impaired true vocal cord adduction

Question 10

Potential signs of damage to CN VII - Facial

Answer 10

• Paralysis of facial nerve muscles
• Poor labial retraction and pursing
• Poor lip seal
• UMN; contralateral lower face
• LMN; ipsilateral upper and lower face, eye closure
• Reduced hyoid elevation
• Dry mouth
• Diminished jaw open/closure
• Loss of taste

Question 11

Potential signs of damage to CN VI - Abucent

Answer 11

• Medial eye deviation - eye/s moving to middle

Question 12

Potential signs of damage to CN III - Oculomotor

Answer 12

• Ptosis - dropping of upper eyelid.
• Diplopia - double vision.