Neurological Exam Flashcards
goal of neurological exam
localize lesions within the nervous system, list possible causes, and evaluate severity/prognosis
requirements for a reflex
intact peripheral (sensory and motor) nerves
intact spinal cord/brainstem
NO cerebral input/processing
results in involuntary movement
requirements for a response
intact ascending/descending pathways
intact spinal cord/brainstem
intact cerebrum
results in voluntary movement
upper motor neurons
neurons that travel from cerebrum to spinal cord and synapse onto LMNs or interneurons
cell bodies: cerebrum
axons: travel to spinal cord
upper motor neuron function
controls voluntary movement
overall INHIBITORY to lower motor neurons
results in DECREASED firing of LMNs
lower motor neurons
neurons that connect CNS with effectors
cell bodies: spinal cord
axons: peripheral spinal/cranial nerves
lower motor neuron function
final effectors of voluntary movement
functional default is “on” - constantly firing
results in INCREASED muscle tone and contraction (if uncontrolled by UMN)
signs of UMN dysfunction
increased reflexes
increased tone
mild, slow atrophy
signs of LMN dysfunction
decreased reflexes
decreased tone
severe, rapid atrophy
signs of C1-C5 lesions
thoracic limbs: UMN signs
pelvic limbs: UMN signs
signs of C6-T2 lesions
thoracic limbs: LMN signs
pelvic limbs: UMN signs
signs of T3-L3 lesions
thoracic limbs: normal
pelvic limbs: UMN signs
signs of L4-caudal lesions
thoracic limbs: normal
pelvic limbs: LMN signs
steps of a neuro exam
- observation (mentation, posture, gait)
- cranial nerves
- postural reactions
- segmental reflexes
- palpation
- +/- sensation
mentation
normal
obtunded
stuporous/semi-comatose
comatose
obtunded
decreased responsiveness to environment
stuporous/semi-comatose
only responds to noxious stimuli
comatose
does not respond to any stimuli
opisthotonus
an abnormal posture where the head and neck are extended dorsally; thoracic limbs are extended and rigid
3 lesions that cause opisthotonus
- decerebrate
- decerebellate
- schiff-sherrington posture
decerebrate
severe lesion to the midbrain causing functional separation of the cerebrum from the rest of the body
mentation: comatose
posture: opisthotonus w/ severe UMN signs
reflexes: normal (if nerves intact)
decerebellate
lesions to the cerebellum (trauma, cerebellar hypoplasia)
mentation: normal
posture: opisthotonus w/ flexion or extension of pelvic limbs
voluntary movement is normal
schiff-sherrington posture
T3 - L5 lesion; causes disruption of an ascending inhibitory pathway up to the thoracic limbs that the spinal cord sends itself; causes disinhibition of LMNs of thoracic limbs –> increased firing
mentation: normal
posture: opisthotonus
voluntary movement is possible
gait descriptors
ambulatory or nonambulatory
paresis
paralysis
lameness
ataxia
circling (in direction of lesion)
dysmetria
mono - one limb
hemi - both limbs on one side
para - both pelvic limbs
tetra - all four limbs
cranial nerve reflexes/responses
- olfactory
- menace response
- visual tracking
- pupillary light reflex
- corneal reflex
- palpebral reflex
- nystagmus
- trigeminofacial reflexes
- symmetry
- gag reflex
olfactory nerve test
blindfold patient and see if they can localize food/treats
not often done - complete loss of olfaction required to see deficits
menace response
make a menacing gesture towards the eye
patient should blink
afferent: CN II
efferent: CN VII
visual tracking
drop a soundless/scentless object (cotton ball) in the visual field
patient should track it as it falls
afferent: CN II
contralateral cerebrum
pupillary light reflex
shine a light in one eye
both pupils should constrict
afferent: CN II
efferent: CN III
isocoric
equal pupils
anisocoria
unequal pupil size
miosis
small/constricted pupil
mydriasis
dilated pupil
corneal reflex
trigeminofacial reflex
touch a damp cotton swab to the cornea
patient should blink and retract globe
afferent: CN V (1)
efferent: CN VII & VI
palpebral reflex
trigeminofacial reflex
touch the medial and lateral cantos of the eye
patient should blink
afferent: CN V (1 & 2)
efferent: CN VII
physiologic nystagmus
vestibulo-ocular reflex - NORMAL
move patients head side to side or up and down
eye globes should move to follow the movement in fast/slow pattern
afferent: CN VIII
efferent: CN III, IV, VI
spontaneous nystagmus
pathologic nystagmus - ABNORMAL
alternating smooth pursuit in one direction followed by saccadic movement in the other direction in the ABSENCE of movement
fast phase moves AWAY from the side of the lesion
trigeminofacial reflexes
afferent: CN V
efferent: CN VII
corneal and palpebral
vibrissae: stimulate whiskers; should blink
lip pinch: pinch maxillary/mandibular lip; should pull lip/move away
nasal stimulation: stimulate inside nares; should move away
facial symmetry
evaluate muscle mass on head/face
efferent: CN VII, CN V(3)
gag reflex
place fingers at the back of the throat
patient should gag
afferent: CN IX, X
efferent: CN IX, X, XII
conscious proprioception
awareness of oneself in space; awareness of all sensory information from the rest of the body
requires sensory and motor function
deficits indicate neurological disease but do not localize lesion
postural reactions
- proprioceptive placing
- hopping
- wheelbarrowing
- extensor postural thrust
- visual placing
- tactile placing
proprioceptive placing
paw knuckling; flip a single paw over while supporting rest of weight
patient should flip paw back over
hopping
life one limb off the ground and push patient off center in opposite direction
patient should hop on weight bearing leg to adjust center of gravity
wheelbarrowing
carry pelvic limbs and push forward
patient should walk forward on thoracic limbs
extensor postural thrust
hold up animal and lower slowly until pelvic limbs reach the ground
patient should adjust feet placement once reaching the ground
visual placing
carry animal towards a surface while extending limb towards the surface
patient should put paw onto oncoming surface
tactile placing
carry animal blindfolded towards a surface and lightly touch paw to the surface
patient should put paw on top of surface
pelvic limb reflexes
- patellar reflex
- gastrocnemius reflex
- flexion/withdrawal reflex
- perineal reflex
patellar reflex
evaluates femoral nerve (L4, 5, 6)
percuss patellar tendon
normal: quadriceps contracts, stifle extends
gastrocnemius reflex
evaluates sciatic nerve (L6, 7, S1)
percuss common calcaneal tendon
normal: contraction of caudal thigh muscles
flexion/withdrawal reflex
pelvic: sciatic nerve
thoracic: musculocutaneous nerve
stimulate interdigital skin
normal: flexion of the limb
perineal reflex
evaluates pudendal nerve (S1, 2, 3)
stimulate skin on each side of perineal region
normal: contraction of anal sphincter
thoracic limb reflexes
- biceps reflex
- triceps reflex
- flexion/withdrawal reflex
biceps reflex
evaluates musculocutaneous nerve
stretch biceps and percuss insertion of biceps tendon onto the radius
normal: contraction of the biceps
triceps reflex
evaluates radial nerve
flex elbow to stretch triceps and percuss insertion of triceps onto the olecranon
normal: contraction of the triceps
cutaneous trunci reflex
bilateral reflex
pinch the skin around the T3 - L3 region of the spine
normal: cutaneous trunci in C8 - T1 region should contract bilaterally
afferent: T3 - L3 cutaneous nerve
efferent: lateral thoracic nerve
lesion in T3 - L3 region effect on cutaneous trunci reflex
absence of reflex caudal to the site of the lesion
blocks ascending sensory pathways from below site
lesion in C6 - T2 region effect on cutaneous trunci reflex
ipsilateral loss of cutaneous trunci contraction regardless of side of stimulation
LMN lesion blocks motor info to one side)
palpation
palpate the head and along the vertebral column to evaluate muscle tone and mass
(check for symmetry, atrophy)
move the head through range of motion
hyperesthesia
abnormal increase in sensitivity to stimuli; apparent painfulness
nociception
the physiological system by which a person feels pain
what are nociceptive pathways protected by
spinal cord - difficult to have loss of function
prognoses for loss of nociception
poor
loss of superficial pain = 85% chance of return to function
loss of deep pain = 50% chance of return to function
when is testing for nociception indicated
paralyzed limbs only
(ambulatory limbs do not need to be tested because already functional)
order of spinal cord loss/regain of function
lost in descending order, regained in ascending order
1. proprioceptive placing
2. voluntary movement
3. superficial pain
4. deep pain
superficial nociception test
use hemostats to pinch interdigital skin and look for a response
(NOT a reflex - patient should turn head up, look at limb, vocalize, etc)
deep nociception test
pinch over a digit (stimulate periosteum) and look for a response
(NOT a reflex - patient should do more than just limb flexion)