Ventricles, Spinal Cord & Cranial Nerves - PowerPoint Presentation

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Ventricles, Spinal Cord & Cranial Nerves

Slide2

Objectives

Identify cranial nerves and describe the function of each

Understand the signs and tests for CN dysfunction

Make an

accurate

model of the ventricle system of the brain

Discuss the clinical implications of dysfunction in the ventricular system

Describe the basic organization of the spinal cord

Slide3

Cranial Nerves and Brain Stem

Please refer to Cranial Nerve Handout

Slide4

A few things first

12 pairs

All ipsilateral symptoms and signs except IV Trochlear (which is also the only CN that exits brainstem on the dorsal surface)

The optic and olfactory nerves are CNS, the rest have axons and receptors that are considered PNS

Can carry

motor

,

sensory

or

mixed

information

ipsilateral = same side

Slide5

t

esting each cranial nerve more or less separately is helpful in diagnostics but not a good way to test function!

Reality is more complex than that!

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1 Olfactory (S)

Receptors>nerve> olfactory bulb> olfactory tract (axon):

Amygdala (fear)

Orbitofrontal cortex (food!)

Thalamus (declarative memory)

Hypothalamus (visceral)

Hippocampus (memory)

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Olfactory Test

Baby powder

Chocolate

Cinnamon

Coffee

Mothballs

Peanut Butter

Soap

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2 Optic Nerve (S)

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Rods and Cones> optic nerve> optic chiasm> optic tract> thalamus

> superior

colliculi > thalamus> occipital lobe

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Optic Pathway

Rods and Cones> optic nerve> optic chiasm> optic tract> thalamus >

s

uperior colliculi > thalamus> occipital lobe

Test:

a

cuity

pupillary light reflex

visual field

Superior colliculi

Slide13

All movements of eye,

except

:

Down and medial (trochlear)

Lateral (abducens)

Directions

of each CN and muscles

3 Oculomotor (M)

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Oculomotor Reflexes

Pupillary Reflex

Consensual

Accommodation

Slide15

Oculomotor Test

Test with abducens and trochlear: basically move stimulus in shape of an H

Signs of Lesion:

Lateral Strabismus (complains of double vision)

Ptosis (droopy eyelid)

Nystagmus (in absence of stimulus)

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4 Trochlear Nerve (M)

Starts in and around oculomotor nucleus, crosses at midbrain, exits out the contralateral side of the dorsal brain stem and then back into the orbit (

eewwwhhh

!)

Test for Lesion

: can’t look down and in (trouble descending stairs)

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5 Trigeminal Nerve (

Mx

)

Sensory

: face, mouth, cornea

Motor

: chewing muscles

Reflexes:

Masseter

Corneal

3 Branches:

Ophthalmic

Maxillary

Mandibular

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Test Trigeminal

Sensation of face

Clamp down jaw, try to open

Palpate masseter and temporal mm

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6 Abducens (M)

Ab

ducts the eye (moves it laterally)

Think about it- adduct would be medial

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7 Facial (

Mx

)

Sensory

: taste tip of tongue

Motor

: facial

expression, lacrimal & salivary glands

Supplies the motor response to the corneal reflex (when the eye is touched)

Test-

facial expression and taste on tip of tongue

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8 Vestibulocochlear (S)

Tests:

Audition- tuning fork

Turn head and see if eyes move slowly in opposite direction

Test for balance by

gently

pushing them

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9 Glossopharyngeal Nerve (

Mx

)

Sensory

: soft palate and pharynx, taste/sensation from posterior tongue, carotid sinus (blood pressure sense)

Motor

: parotid gland (salivary gland) and 1 pharyngeal mm

Sensory portion of the gag and swallowing reflexes so that’s how it is tested

Slide23

10

Vagus

(

Mx

)

Sensory: larynx & pharynx

Motor: autonomic functions of gut, cardiac (inhibition), vocal cords, swallowing

Motor component of the gag and swallow reflexes

Test: reflexes, hoarseness, uvula (thing in the back of your throat)

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11 Spinal accessory nerve

Innervates shoulder and neck mm

Test sternocleidomastoid and trapezius

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12 Hypoglossal Nerve

Movement of the tongue

Test

: stick tongue out, it will point to the side of the lesion, make sure they can push equally on both checks with tongue

Slide26

Basic Organization of the

Spinal Cord

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8 Cervical

12 Thoracic

Lumbar

5 Sacral

1 Coccygeal

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S

1

Slide29

Root

Muscle(s)

Action

C5

Deltoid

Shoulder Abduction

C5

Infraspinatus

Humeral external rotation

C5, 6

Biceps

Flexion

of supinated forearm

C6

Extensor carpi radialis, ulnaris

Wrist extension

C7

Extensor digitorum, triceps

Finger extension, forearm extension

at elbow

C8, T1

Interossei, lumbricals

Finger ab and ad (spread and close against force)

L2-L4

Quadriceps,

iliopsoas, adductors

Knee extension, thigh on hip flexion, thigh adduction

L5

Anterior tibial, extensor halluces

Ankle and big toe

dorsiflexion (walk on heels)

S1

Gastrocnemius

Ankle

plantar flexion (walk on tip toes)

Slide30

Same magnification, cross sections

White matter is dark, grey is light

Dorsal on top, ventral on bottom (imagine a person laying on stomach)

Dorsal column

Lateral column

Ventral column

Ventral horn

Dorsal horn

Lateral horn

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Dorsal=sensory

Ventral=motor

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Ventricles

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