Pathologies associated with cranial nerves

Question 1

Name the nerves that innervate the muscles in the eye
Right
Sup rect  Inf ob
Lat rect  Med rect
Inf rect  Sup ob

Left
Inf ob Sup rect
Med rect Lat rect
Sup ob Inf rect

Answer 1

Right
III III
VI III
III IV

Left
III III
III VI
IV III

Question 2

What pathologies are associated with damaged trochlear nerves and why

Answer 2

Trochlear nerve prone to injury due as its the

• thinnest
• longest route in skull

Normally a medial depressor, loses this ability

Question 3

What pathologies are associated with damaged abducens nerves and why

Answer 3

Abducens nucleus can be affected independently from other nuclei
-nucelus is distant from others

Normally a lateral rotator, loses this ability

Question 4

What pathologies are associated with damaged oculomotor nerves

Answer 4

Ptosis, restricted eye movemenrs

Pupillary reflex affected

Question 5

What nerves and structures emerge out of the superior orbital fissure
What pathologies here can affect nerve function

Answer 5

Oculomotor
Trochlear
Trigeminal (opthalmic)
Abducens

Anterior to cavernous dural sinus filled with venous blood
Internal carotid artery also found here

Any obstruction of blood flow/bleeds can compress nerves

Question 6

What are the causes of trigeminal neuralgia

Answer 6

Compression by blood vessels
Demyelination
Herpes virus infection
Tooth, jaw infection
Brainstem tumors

Leads to ipsilateral pains, can lead to suicide

Question 7

What are the causes of facial nerve palsy
What can happen as a result
What are the symptoms associated with facial nerve pasly

Answer 7

Stroke
Tumours
Infection
Bell’s palsy

Unilateral facial hemiplegia => drooping eye and corner of mouth, loss of nasolabial fold

Question 8

What 2 nerves are associated with the internal auditory meatus and what pathologies can occur here

Answer 8

Facial nerve
Vestibulocochlear nerve

Acoustic neuromas here can compress facial nerve

Question 9

Describe how a winged scapula can occur

Answer 9

Blunt trauma and surgical complications

Damages accessory nerve

Lose innervation of trapezius and sternocleidomastoid => winged scapula

Question 10

What happens when tumors compress glossopharyngeal, vagus, accessory and hypoglossal nuclei in the medulla

Answer 10

Dysphoria
Unilateral weakness, wasting, fasciculation of tongue
Gag reflex supression
Unilateral wasting of sterncleidomastoid and trapezius
Changed taste sensation

Question 11

How does motor neuron disease arise

What are the associated symptoms

Answer 11

Damage to motor nuclei

• Corticobulbar, corticospinal
• Nucleus ambiguus
• Hypoglossal nucleus

Dysphoria
Dysphonia
Dysarthria
Weakness, spasticity of tongue

Question 12

What are the 5 symptoms of unilateral brain lesions

Answer 12

If in brain stem
Ipsilateral CN dysfunction

If in cortex
Contralateral spastic hemiparesis
Contralateral hemisensory loss
Hyperreflexia

If in cerebellum
Ipsilateral incoordination

Question 13

What are the 2 symptoms of bilateral brain lesions

How can these arise

Answer 13

Coma/death

Trauma
Stroke
Tumor