SA neurology Flashcards
what are the three divisions of the brain?
forebrain
brainstem
cerebellum
what are the divisions of the forebrain?
cerebral cortex
diencephalon
what are the divisions of the brainstem?
midbrain
pons
medulla oblongata
what are the functional divisions of the spine?
C1-C5
C6-T2
T3-L3
L4-S3
is the white matter found on the centre or periphery of the spinal cord?
peripheral
what makes up the white matter of the spinal cord?
nerve tracts (sensory and motor)
what makes up the grey matter of the spinal cord?
interneurons and motor neurons
how many pairs of spinal nerves are there?
36
how many pairs of cranial nerves are there?
12
where are the motor neurons cell body found?
ventral horn of spinal cord
where are the cell bodies of sensory axons found?
dorsal root ganglion of spinal cord
what create myelination of the PNS?
Schwann cells
what are the three parts of the neuromuscular junction?
axon terminal
synaptic cleft
endplate of skeletal muscle
where can brain lesions be localised to?
forebrain
brainstem
cerebellar
vestibular
where can neuromuscular system lesions be localised to?
peripheral nerve
neuromuscular junction
muscle
what is the ANS responsible for?
involuntary actions (visceral functions)
what are the two divisions of the ANS?
sympathetic
parasympathetic
where are the cell bodies of the sympathetic nervous system found?
thoracolumbar
where are the cell bodies of the parasympathetic nervous system found?
craniosacral
what happens to the detrusor and sphincters during bladder filling?
detrusor - relax
sphincter - tone increases
what happens to the detrusor and sphincters during bladder emptying?
detrusor - contract
sphincters - relax
how can bladder incontinence be classified?
UMN
LMN
where are lesions for UMN bladder incontinence seen?
cranial to sacral spinal cord
how do bladders with UMN bladder incontinence present?
distended and difficult to express
where are lesions causing LMN bladder incontinence seen?
sacral spinal cord
sacral spinal nerves
how do bladders with LMN bladder incontinence present?
distended, overflow and dribble
where does the 1st order sympathetic neuron of the eye travel?
brainstem then caudally in cervical spinal cord
where does the 2nd order sympathetic neuron of the eye travel?
exits spinal cord at brachial plexus (T1-T3) the travels rostrally in vagosympathetic trunk to the cranial cervical ganglion
what does the sympathetic supply to the eye innervate?
pupil dilator
smooth cilaris muscle
smooth muscle of blood supply and sweat glands of head
what is the function of grey matter?
information processing
what does grey matter of the brain contain?
cell bodies
where is grey matter found in the brain?
peripherally
where is white matter found in the brain?
centrally (deep)
what does white matter contain?
myelinated axon tracts
what are the three meninges?
dura mater (thick) arachnoid (thin) pia mater (thin)
what is found in the subarachnoid space?
CSF, blood vessels, nerve roots
what direction does CSF travel?
caudally
what triggers the flow of CSF?
pulsations of blood in choroid plexus
what route does CSF take through the brain?
lateral ventricles intraventricular foramen 3rd ventricle mesencephalic aqueduct 4th ventricle lateral apertures subarachnoid space
what is CN I?
olfactory
what is CN II?
optic
what is the function of the olfactory nerve?
conscious perception of smell
where is the cell bodies of the olfactory nerve found?
olfactory epithelium
where do the axons of the olfactory nerve pass through?
cribriform plate (synapse in olfactory bulb)
what is the optic nerve myelinated by?
oligodendrocytes (surrounded by meninges)
where does the optic nerve enter the skull?
optic canal
what is CN III?
oculomotor
what is CN IV?
trochlear
what does the oculomotor nerve innervate?
dorsal, vental, medial rectus
ventral oblique extraocular
levator palpebrae superioris
what does the parasympathetic component of the oculomotor control?
pupillary constriction
where is the nucleus of the oculomotor nerve?
midbrain
where does the oculomotor, trochlear and abducens nerves exit the skull?
orbital fissure
what does the trochlear nerve innervate?
dorsal oblique muscle
where is the nucleus of the trochlear nerve?
midbrain
what are the functions of the trigeminal nerve?
sensory to face
motor to masticatory muscles
what are the branches of the trigeminal nerve?
ophthalmic
maxillary
mandibular
where is the motor nuclei of the trigeminal nerve?
pons
where is the sensory nuclei of the trigeminal nerve?
brainstem
what is CN V?
trigeminal
what is CN VI?
abducens
what does the abducens nerve innervate?
lateral rectus
retractor bulbi
where is the nucleus of the abducens?
medulla
what is CN VII?
facial
what is CN VIII?
vestibulocochlear
what does the facial nerve innervate?
muscles of facial expression
sensory - rostral 2/3 of tongue
what is the function of the vestibulocochlear nerve?
hearing and vestibular function
what is innervated parasympathetically by the facial nerve?
lacrimal, mandibular, sublingual glands
what is CN IX?
glossoparyngeal
what is CN X?
vagus
what does the glossopharyngeal nerve innervate?
motor - pharynx and palate
sensory - caudal 1/3 of tongue
where is the nuclei of glossopharyngeal and vagus nerve found?
medulla
what does the vagus nerve innervate?
motor - larynx, pharynx, oesophagus
sensory - larynx, pharynx, thoracic/abdominal viscera
what is CN XI?
accessory
what is CN XII?
hypoglossal
what is the function of the hypoglossal nerve?
motor innervation to tongue
where is the nucleus of the accessory and hypoglossal nerve?
medulla
where do the LMN of the forelimbs originate?
C6-T2
where do the LMN of the hindlimbs originate?
L4-S3
what are the stages of a reflex?
stimuli
sensory nerve, dorsal root and synapse in grey matter
connects directly or indirectly to motor nerve
what is nociception?
perception of pain
where in the brain is pain perceived?
forebrain
what is tested by testing reflexes?
LMN system
what are the functions of the UMN system?
initiate voluntary movement
maintain muscle tone
what is the pyramidal UMN for?
skilled movement (poorly developed in animals)
where does the pyramidal UMN system start?
cerebral cortex (pass through pyramids in brainstem)
what is the functions of the extrapyramidal UMN system?
tonic mechanism for support of body against gravity
recruit spinal reflexes
where do most extrapyramidal UMN systems start?
brainstem (don’t pass through pyramids)
what is the function of proprioception?
sensory system detecting position/movement of muscles/joints
what tracts are involved in unconscious proprioception?
spinocerebellar
what tracts are involved in conscious proprioception?
spinal
what is the vestibular system for?
maintaining balance
maintains orientation relative to gravity
maintains position of eyes, neck, trunk, limbs relative to the head
what are the 2 divisions of the vestibular system?
peripheral
central
what makes up the peripheral vestibular system?
inner ear
vestibulocochlear nerve
what makes up the central vestibular system?
vestibular nuclei (brainstem) cerebellum
what in the inner ear contributes the the vestibular system?
3 ducts orientated at right angles to each other filled with endolymph
what is the function of the cerebellum?
control motor activity (regulator)
maintain balance
what sign associated with walking will be present if the UMN or LMN is damaged?
paresis/paralysis
what sign associated with walking will be present if the general proprioception, cerebellum or vestibular system is damaged?
ataxia
where does the optic nerve cross the brain?
optic chiasm
where is the lesion if an animal has no menace or pupillary light reflex?
before optic chasm (eye or optic nerve)
where is the lesion if an animal has no menace but a functioning pupillary light reflex?
forebrain
what is the function of the forebrain?
behaviour
decision making
conscious perception of sensory systems
what are the functions of the ascending reticular activating system (ARAS)?
arouse cortex
awake brain to conscious level
prepare brain to receive sensory information
what should be observed on a neurology consult?
mentation
behaviour
posture
gait
where can lesions be to cause problems with mentation?
forebrain
brainstem
what ways can mentation be described?
alert disorientated/confused depressed stuporous (unconscious but feel pain) comatose
where is a lesion of a disoriented/confused animal usually found?
forebrain
where is a lesion that effects the behaviour of an animal found?
forebrain
where is a lesion found that causes circling?
forebrain (circle towards the lesion)
what are the most common postural defects?
head tilt
head turn
where is a lesion found that causes a head tilt?
vestibular system
where is a lesion found causing a head turn?
forebrain (brainstem sometimes)
what are the two types of rigidity?
decerebrate
decerebellate
what is a decerebrate rigidity?
all limbs extended and rigid
where is a lesion found if there is decerebrate rigidity?
brainstem
what is decerebellate rigidity?
extension of forelimbs
where is a lesion found if there is decerebellate rigidity?
cerebellum
what is the difference in mentations between decerebrate and decerebellate rigidity?
decerebrate - comatose
decerebellate - normal
how do patients with Schiff-sherrington present?
hyperextension of thoracic limbs and paralysis of pelvic limbs
where are lesions causes schiff-sherrington found?
thoracic or cranial lumbar spine
how can gait be described?
ataxia
paresis
paralysis
where will a lesion be found if there is ataxia?
spinal
vestibular (off balance)
cerebellar (drunk)
what is ataxia?
uncoordinated gait
what is paresis?
weakness/reduced voluntary movement
what is paralysis?
complete loss of voluntary movement
what are the types of paresis?
ambulatory
non-ambulatory
what are the 4 parts of a neurological clinical exam?
postural reaction
spinal reflex/muscle tone
spinal pain
cranial nerves
what is being tested during a postural test?
awareness of precise position/movement of the body (proprioception)
what tests can be done for postural reactions?
paw postion
hopping
placing response
what is the most important spinal reflex to test?
withdrawal
what are the two most reliable myotactic reflex tests?
patellar
perineal
what areas can the cutaneous trunci reflex be used for?
brachial plexus
T3-L3
what is looked at when observing the reflex response?
pain perception
how is spinal pain assessed?
palpate spine (increasing pressure) move neck (resistance/reluctance) move tail
what are the cranial nerve tests?
palpebral corneal physiological nystagmus menace response nasal mucosa stimulation pupillary light response gag
what nerves does the palpebral reflex test?
trigeminal (input)
facial (output)
what nerves does the corneal reflex test?
trigeminal (input)
abducens/facial (output)
what nerves does the physiological nystagmus test?
vestibulocochlear (input)
oculomotor, trochlear, abducens (output)
what is the physiological nystagmus test particularly useful for?
patients with raised intracranial pressure (puts pressure on nerves)
how can the vestibular system be challenged when assessing nystagmus?
put animal upside down
what is strabismus?
abnormal position of the eyeball that the animal can’t overcome
what is nystagmus?
rhythmical, involuntary movements of the eye
what is horners syndrome a sign of?
sympathetic disfunction to the eye
what is seen in small animals with horners syndrome?
miosis
3rd eyelid protrusion
ptosis of upper eyelid
what is seen in horses with horners syndrome?
miosis
ptosis of upper eyelid
excessive sweating
what is assessed with nasal mucosa stimulation?
trigeminal, forebrain, brainstem
what is assessed by the menace response?
optic, forebrain, cerebellum, brainstem, facial
what is tested by the pupillary light response?
optic, brainstem, oculomotor
what is tested by the gag reflex?
glossopharyngeal, vagus, brainstem
where is the lesion if the dog having seizures?
forebrain
what are possible clinical signs of forebrain lesions?
disorientation/depression contralateral blindness normal gait circling, head press, pacing decreased postural response seizure/behaviour change
what are possible clinical signs of brainstem lesions?
depression, stupor, coma CN III-XII deficit vestibular signs paresis decerebrate rigidity decreased postural response respiratory/cardiac abnormality
what are possible clinical signs of cerebellar lesions?
normal mentation abnormal menace vestibular signs hypermetria/ataxia intention tremors decerebellate rigidity
what are possible clinical signs of vestibular lesions?
head tilt
nystagmus
ataxia
positional strabismus
what is spinal shock?
flaccid paralysis with loss of spinal reflexes
when does spinal shock happen?
after acute severe injury to spinal cord
how long does it take reflexes to return in spinal shock cases?
up to 12 hours
what is a grade 1 spinal injury?
no deficit just spinal pain
what is a grade 2 spinal injury?
ambulatory paresis
what is a grade 3 spinal injury?
non-ambulatory paresis
what is a grade 4 spinal injury?
paralysis
what is a grade 5 spinal injury?
paralysis and loss of pain sensation
what is the main clinical sign of neuropathies?
reduced reflex
what are neuropathies?
damage to nerves
how do polyneuropathies effect the forelimb and hindlimb reflexes?
reduce both
what is the main clinical sign of myopathies?
generalised weakness/exercise intolerance