Week 2 Tutorial - Cranial Nerves

Describe the structure of the neuron and identify disorders. Describe the gross neuroanatomy of the brain – the surface and internal structures of the brain. Explain the functional divisions of the nervous system. Explore the surface and internal structures of the brain – and their disorders. Explore the motor system and how it functions Spinal nerves Cranial nerves

How many cranial nerves are there?

12

What nerve/s do we think about for voice?

Vagus Nerve

What nerve/s do we think about for Articulation?

Hypoglosal nerve and trigemneal nerve ( mandibular nerve)

What nerve/s do we think about for cough/swallow?

Vagus nerve (for the cough) and glossopharangeal nerve ( for the swallow)

What nerve/s do we think about for Hearing?

Vestibular cochlear nerve or Auditory nerve

What are the three branches of trigeminal nerve?

1. Ophthalmic

2. Maxillary

3. Mandibular

What is a way to remeber the function of the vagus nerve?

Vagus means “wandering” so think of broad functions for this nerve - respiratory system, digestive system, circulatory system

What is cranial nerve I and its function?

Olfactory nerve - Sensory fucntion is smell

What is cranial nerve II and its function?

Optic nerve - Sensory function is vision

What is cranial nerve III and its function?

Occulomotor nerve - motor function is extraocular eye muscles;

reflexive constriction of pupil

How is the oculomotor nerve tested?

OME

What is cranial nerve IV and its function?

Trochlear nerve - Extraocular eye muscles depression, adduction of

the eye

What is cranial nerve V and its function (both sensory and motor function)?

Trigemenal nerve:

Sensory function: Light touch, pain & temperature to face mouth, sensory to anterior 2/3 tongue & teeth

Motor function: Muscles of the jaw for chewing and speech

What is cranial nerve VI and its function?

Abducens Nevre - motor function - extraocular eye muscles

What is cranial nerve VII and its function (both sensory and motor)?

Facial Nerve

Sensory function: sensation of ear and tastes anteriro 2/3 tongue

Motor function: Muscles of facial expression (lips) and lips

How is the facial nerve (VII) tested?

OME

What is cranial nerve VIII and what is its function (sensory)?

Vestibularcochlear nerve

Sensory - Hearing Vestibular function &

balance

What is cranial nerve IX and what is its function (sensory and motor)?

Glossopharyngeal Nerve

Sensory function: Taste posterior 1/3 tongue; General sensation posterior 1/3 tongue, palate & oropharynx; Gagreflex

Motor function: Stylopharyngeus muscle – contributes to swallowing

Parotid Salivary gland (autonomic)

What is cranial nerve X and what is its function (sensory and motor)?

Vagus nerve

Sensory function: General sensation from pharynx, larynx Taste epiglottis & pharynx

Motor function: Soft palate, Pharynx, Larynx (vocal cords) Oesophagus, stomach, hear

What is cranial nerve XI and what is its function (motor)?

Accesory nerve (spinal)

Motor function: Head / shoulder muscles

What is cranial nerve XII and what is its function (motor)?

Hypoglossal Nevre

Motor function: Tongue movement

Acronym to remember all the nerves

Oh Oh Oh, to touch and feel very good velvet, Simply heaven

What is the corticobular tract?

Primary upper motor neuron pathway that connects the cerebral cortex to the motor nuclei of the cranial nerves in the brainstem.

What cranial nerves decussate?

1. Optic Nerve (II)

2. Trochelar Nerve (IV)

3. Facial Nerve (VII)

4. Hypoglossal Nerve (XII)

When examining the function of the cranial nerves you must determine:

1. Whether there is an abnormality

2. The nature of the abnormality

3. The extent of the abnormality

What features do you look at to access muscle function

1. Symmetry – at rest & during movement

2. Muscle bulk – signs of “wasting” or “atrophy” (LMN)

3. Fasciculation – muscle “twitching” at rest (LMN)

4. Muscle strength – movement against gravity / resistance

5. Muscle tone – resistance of a relaxed muscle to passive movement

6. Hypotonia – reduced tone / flaccidity (LMN)

7. Hypertonia – increased tone / rigidity / spasticity (UMN)

8. Reflexes – hyper / hyporeflexia

9. Coordination- movements are steady and equal in rate and timing