Name the cranial nerves involved in special sensory function
- Olfaction (I)
- Vision (II)
- Taste (VII, IX and X)
- Hearing - and balance (VIII)
Name the cranial nerves involved in general sensation
- Trigeminal Nerve V3
- The ear from the VII (facial)
- IX (glossopharyngeal)
Name the cranial nerves involved in control of muscle activity
- Eye muscles – III (oculomotor), IV (trochlear) and VI (abducence) (LR6,SO4, rest 3)
- Muscles of mastication – V3 (trigeminal)
- Muscles of facial expression – VII (facial)
- Muscles of larynx and pharynx – mainly X (vagus)
- Sternomastoid and trapezius muscles - XI (accessory)
Name the cranial nerves that are parasympathetic and involved with autonomic functions
- Pupillary constriction – III (oculomotor)
- Lacrimation – VII (facial)
- Salivation – submandibular and sublingual glands – VII (facial)
- Salivation – parotid gland - IX (glossopharyngeal)
- Vagal (X) input to organs in thorax and abdomen
How would you test Olfactory nerve
Smell-unilateral or bilateral loss
How would you test Optic nerve
visual acuity, visual fields, pupillary reactions, fundoscopy, colour vision
How would you test the oculomotor, trochlear and abducens nerve
ptosis, pupil of equal size, pupillary reactions, eye movements
How would you test the trigeminal nerve
power in the muscles of mastication, corneal reflex, jaw jerk
How would you test the facial nerve
muscle of fascial expression, corneal reflex, taste
How would you test the vetsibulochlear nerve
hearing using Rinne’s and Weber’s tests, Vestibular function using Dix-Hallpike manoeuvre and Untenberger’s test
How would you test the glossopharyngeal nerve
movement of palate, gag reflex, quality of speech, quality of cough
How would you test the accessory nerve
- head turning and shoulder shrugging
How would you test the hypoglossal nerve
appearance, movement and power of tongue
Name the afferent and efferent nerves involved in pupillary reflex
afferent – II ; efferent – III
Name the afferent and efferent nerves involved in corneal reflex
afferent – V ; efferent – VII
Name the afferent and efferent nerves involved in Jaw jerk
V
Name the afferent and efferent nerves involved in gag reflex
- afferent – IX ; efferent - X
Where is the oculomotor and trochlear located
Midbrain
Where is the Trigeminal, abducent and facial nerve located
Pons
Where is the Vestibulochlear nerve located
Pontomedullary Junction
Where is the Glossopharyngeal, Vagus, Accessory and Hypoglossal located
Medulla
Bilateral III signs
Midbrain
III +IV+VI signs
Superior orbital fissure
V + VIII signs
cerebellopontine angle
How can cranial nerves be damaged
- Within brain- ischaemia, tumour
- Crossing the sub-arachnoid space- meningitis
- Outside the skull- by base of skull tumours arising in nasopharynx
Name some features of Optic Neuritis
- Demyelination within the optic nerve
- Monocular visual loss
- Pain on eye movement
- Reduced visual acuity
- Reduced colour vision
- Optic disc may be swollen
- Often associated with MS
Describe Parasympathetic control of the the pupillary response
- constriction of the pupil
- loss of parasympathetic input results in a fixed, dilated pupil
- e.g. complete third nerve palsy
Describe sympathetic pupillary response
- pupillary dilatation
- damage anywhere within the sympathetic pathway can lead to a constricted pupil
Name some causes of dilated pupils
- Youth
- Dim lighting
- Anxiety, excitement
- “Mydriatic” eye drops
- Amphetamine, cocaine overdose
- Third nerve palsy
- Brain death
Name some causes of small pupils
- Old age
- Bright light
- “Miotic” eye drops
- Opiate overdose
- Horner’s Syndrome
Name causes of isolated third nerve palsy
o Microvascular- diabetes, hypertension- painless, pupils spared
o Compressive- posterior communicating artery aneurysm, raised ICP- painful, pupil affected
• Isolated fourth nerve palsy- Trochlear
Name causes of isolated sixth nerve palsy
o Idiopathic
o Diabetes
o Meningitis
o Raised ICP
Name features and causes of Nystagmus
o Congenital o Serious visual impairment o Peripheral vestibular problem o Central vestibular / brainstem disease o Cerebellar disease o Toxins (medication and alcohol)
Describe Bell’s Palsy
LMN type Unilateral weakness • Often preceded by pain behind ear • Eye closure affected • Risk of corneal damage • Treated with steroids • Usually good recovery
Describe Supranuclear lesion
Lesion in the cortex
UMN type
Forehead unaffected due to bilateral nerve supply to the upper part of the face
What is Dysarthria
– disordered articulation, slurring of speech
What is Dysphagia
– difficulty swallowing
When does Dysarthria and Dysphagia occur together
Bulbar abd pseudobulbar palsy
Describe Bulbar palsy
Bilateral LMN lesion affecting IX-XII
Name causes of Bulbar palsy
MND
Polio
Tumours
Vascular lesions of the medulla and syphilis
What are the clinical features of bulbar palsy
Wasted, fasciculating tongue Dysarthria Dysphonia Dysphagia Beware of feeding these patients
Describe Pseudobulbar palsy
Bilateral UMN lesion
In vascular lesions of both internal capsules
Name clinical symptoms of Pseudobulbar palsy
Dysarthria Dysphonia Dysphagia Spastic immobile tongue Brisk jaw jerk Brisk ag reflex