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 ID: 918050
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Slide1
Ventricles, Spinal Cord & Cranial Nerves
Slide2Objectives
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
Slide3Cranial Nerves and Brain Stem
Please refer to Cranial Nerve Handout
Slide4A 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
Slide5t
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!
Slide6Slide7Slide81 Olfactory (S)
Receptors>nerve> olfactory bulb> olfactory tract (axon):
Amygdala (fear)
Orbitofrontal cortex (food!)
Thalamus (declarative memory)
Hypothalamus (visceral)
Hippocampus (memory)
Slide9Olfactory Test
Baby powder
Chocolate
Cinnamon
Coffee
Mothballs
Peanut Butter
Soap
Slide102 Optic Nerve (S)
Slide11Rods and Cones> optic nerve> optic chiasm> optic tract> thalamus
> superior
colliculi > thalamus> occipital lobe
Slide12Optic 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
Slide13All movements of eye,
except
:
Down and medial (trochlear)
Lateral (abducens)
Directions
of each CN and muscles
3 Oculomotor (M)
Slide14Oculomotor Reflexes
Pupillary Reflex
Consensual
Accommodation
Slide15Oculomotor 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)
Slide164 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)
Slide175 Trigeminal Nerve (
Mx
)
Sensory
: face, mouth, cornea
Motor
: chewing muscles
Reflexes:
Masseter
Corneal
3 Branches:
Ophthalmic
Maxillary
Mandibular
Slide18Test Trigeminal
Sensation of face
Clamp down jaw, try to open
Palpate masseter and temporal mm
Slide196 Abducens (M)
Ab
ducts the eye (moves it laterally)
Think about it- adduct would be medial
Slide207 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
Slide218 Vestibulocochlear (S)
Tests:
Audition- tuning fork
Turn head and see if eyes move slowly in opposite direction
Test for balance by
gently
pushing them
Slide229 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
Slide2310
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)
Slide2411 Spinal accessory nerve
Innervates shoulder and neck mm
Test sternocleidomastoid and trapezius
Slide2512 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
Slide26Basic Organization of the
Spinal Cord
Slide278 Cervical
12 Thoracic
Lumbar
5 Sacral
1 Coccygeal
Slide28S
1
Slide29Root
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)
Slide30Same 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
Slide31Dorsal=sensory
Ventral=motor
Slide32Ventricles
Slide33Slide34Slide35