Neurologic Exam Flashcards
cranial nerves
- 12 pairs emerging from base of brain (mainly brainstem) within the skull
- Motor, sensory or specialized functions
- Symptoms specific to area and function of nerve
- CN deficits can be due to nerve or brain lesions
- CN are technically peripheral nerves even though they come out of the brain
spinal cord
- Extends from medulla (brainstem) to L1-2
- Becomes cauda equina below L2
- Contains motor and sensory nerve pathways
- Mediates reflex activity of deep tendon reflexes
- Spinal nerves form from anterior and posterior nerve roots from spinal cord and combine with fibers from other levels in plexuses outside the cord, forming peripheral nerves
- Sensory (afferent) and motor (efferent) fibers
spinal nerves
- Connect spinal cord with muscles and peripheral sensory receptors
- Nerve roots exit vertebral (spinal) column through neural foramina
- Each spinal nerve has an anterior (motor) and a posterior (sensory) root
neural pathways
- Three Main “Super-Highways” of brain and spinal cord
- -Corticospinal Tract
- –Motor
- -Spinothalamic Tract
- –Sensory
- -Posterior Column
- –Sensory
- Primarily located in brainstem and spinal cord
corticospinal tract
- White matter connection between cerebral cortex and medulla in the anterior horn cells of the spinal cord
- -Motor pathway
- Responsible for muscle tone and skilled, voluntary movements
- Damage causes upper motor neuron symptoms
- -Spasticity, brisk reflexes, positive Babinski
- When UMN systems are damaged above the crossover of its tracts in the medulla, motor impairment develops on the contralateral (opposite) side; in damage below the crossover, motor impairment occurs on the ipsilateral (same) side of the body.
locating the source of motor deficits
- If corticospinal tract damaged or destroyed, motor function is affected below the level of injury
- If neurons are damaged above crossover tracts in medulla, motor impairment is on opposite (contralateral) side
UMN or LMN
- UMN problem (CNS to cord)
- -Affected extremity is spastic
- -Increased muscular tone
- -Increased reflexes
- LMN problem (CNS to peripheral nerve)
- -Affected extremity is flaccid
- -Decreased muscular tone
- -Decreased reflexes
- Upper motor neurons lie in motor strip of cerebral cortex and brainstem nuclei; axons synapse with motor nuclei in brainstem (CN) and spinal cord (peripheral nerves)
- Lower motor neurons have cell bodies in spinal cord (anterior horn cells); axons transmit impulses through anterior roots and spinal nerves into peripheral nerves, terminating at neuromuscular junction
spinothalamic tract
- Transmits pain, temp, and crude touch sensation from spinal cord to thalamus
- Fibers cross to contralateral side in cord and travel up
- Lesions cause contralateral anesthesias
- -Loss of pain
- -Loss of temperature
- Crude touch is a sensation perceived as light touch but without accurate localization
posterior columns
- Transmit fine touch, vibration, and proprioception from spinal cord to thalamus
- Fibers cross to contralateral side in the medulla
- Fine touch: touch that is accurately localized and finely discriminating
- Proprioception: position sense; this pathway is assessed with the Romberg test
- stereognosis assessed in this column: ability to recognize an object in your hand
- Specialized touch
- -These don’t cross until the medulla whereas spinothalamic tract cross over in the spinal cord section
motor exam
- (corticospinal tract) – combined with MSK system
- Myotomes (peripheral nerves to muscles)
- Body position at movement and rest
- Involuntary movements: tremors, tics, fasciculation
- Muscle bulk: atrophy
- Muscle tone: rigidity to passive ROM, spasticity, cog wheeling
- Muscle strength: resistive ROM
sensory exam
- Dermatomes (spinal nerves)
- Deep tendon reflexes (spinal reflexes)
- Sensation (spinothalamic tract, posterior columns)
cerebellum exam
balance & coordination
Biceps flexion innervation
C5 C6
Triceps extension innervation
C6 C7 C8
Grip innervation
C7 C8 T1
Hip flexion innervation
-iliopsoas
L2 L3 L4
Hip adduct innervation
L2 L3 L4
Hip abduct innervation
L4 L5 S1
Hip extend innervation
L2 L3 L4
Knee extend innervation
-quadriceps
L2 L3 L4
Knee flex innervation
-hamstrings
L4 L5 S1
Dorsiflex innervation
L4 L5
Plantarflex innervation
S1
Atrophy of the thenar eminence
may suggest median nerve damage
atrophy of hypothenar
may be ulnar nerve damage
sensory receptors found in
- Skin
- Mucous membranes
- Muscles, tendons
- Viscera
Sensory function
- Skin receptors for different kinds of sensation send afferent impulses to spinal cord via peripheral and spinal nerves
- Impulses travel via spinothalamic tract or posterior columns to thalamus
- Impulses then travel to cortex for fine interpretation
Dermatomes
- A dermatome is a band of skin innervated by the sensory root of a single spinal nerve
- Locating abnormal sensation to a dermatome identifies location of injury
Important dermatome levels
*T4 = nipple
*T10 = umbilicus
*C6 = thumb
C8 = ulnar side of handL4 = knee and medial maleolus
*S1 = lateral maleolus
S2 = heel
L5 = between big toe and little toe
Dermatomes start from embryology
spinal reflexes: deep tendon response
- Involuntary reflex arc between afferent and efferent nerves in spinal cord
- -Sensory impulse directly stimulates motor fiber
- Reflex – involuntary stereotypical response
- Each reflex involves specific spinal segment – abnormal finding will be helpful in location of problem
Hyperactive DTR
suggests central nervous system disease
Blunted or absent DTRs
suggest damage to the corresponding spinal nerve, damaged peripheral nerves or disease of the muscle
innervation of patella reflex
L2 L3 L4
Reflex
Each spinal nerve separates into ventral (posterior) and dorsal roots. Motor fibers are in ventral root carrying impulse from cord to muscles, sensory fibers in dorsal( anterior) root carry impulse from sense receptors to the cord, some of those continue up the cord to the brain for interpretation while other will immediately initiate a motor response
reflex arc
Stretch receptors in muscle respond to tap thus sending a signal
deep tendon reflexes
- Increased or decreased?
- Grading scale
- -0 to 4+; 2+ normal
- Reflexes tested
- -Biceps – C5, C6
- -Triceps – C6, C7
- -Brachioradialis – C5, C6
- -Patella – L2, L3, L4
- -Achilles – S1
- -Abdominal – T8-12
- -Plantar – L5, S1 (Babinski response)
Babinski’s response
-when the big toe dorsiflexes (norm-plantarflexion toward stimuli) and other toes fan. Indicates CNS lesion, drug or ETOH intoxication, postictal state of seizure.
-Positive Babinski is abnormal, indicating a central nervous system lesion in the corticospinal tract
often doing this on patients who are unconcious
-Good for evaluation of patients with suspected spinal cord, cauda equina, or CNS problems or lesions
-Positive response babinski is seen in newborn because their CNS isnt fully formed
-Normal response is toes going down or clenching in (aka negative response)
components of sensory exam
- Light touch (both pathways)
- Pain (spinothalamic)
- Position and vibration (posterior columns)
- Discriminative sensations (cortex or posterior columns) – must have intact sensation
- -Stereognosis
- -Graphesthesia
- -2 point discrimination
- -Point localization
- -Extinction
sensory exam: light touch
Light touch
- Eyes closed and have pt tell you when they feel the cotton ball
- Compare bilaterally, “do they feel the same?”
- Compare distal to proximal on each extremity, “do they feel the same?”
sensory exam: pain
- Compare right and left sides
- Pain (sharp or dull)
- -Eyes closed: Each time you feel me touch you, tell me if it is sharp or dull
- -Once you touch one side (R) then the other (L) ask the patient, “do they feel the same?”
- -Use dull as control
- -Compare distal to proximal on each extremity; “do they feel the same?”
- Performed on face, UE, LE
hemisensory loss
lesion in spinal cord or higher
symmetrical distal loss
polyneuropathy, “stocking glove” in DM
anesthesia
absence of touch sensation
hypoesthesia
decreased touch sensitivity
hyperesthesia
increased touch sensitivity
analgesia
absence of pain sensation
hypoalgesia
decrease of pain sensation
hyperalgesia
increase of pain sensation
sensory exam: vibration
- 128 Hz tuning fork
- Eyes closed
- IP of thumb and great toe – bilaterally
- Instruct the patient, “tell me what you feel”
- Then instruct, “Tell me when it stops”
sensory exam: proprioception
Position Sense
- Eyes closed
- DIP joint of index finger – isolate this joint by stabilizing the PIP joint
- IP joint of great toe – stabilize MP joint
- Hold digit by the sides
- “Tell me which position I stopped in, up or down”
- Compare bilaterally
sensory loss
Findings of position and vibratory sense
- Vibratory sense first sensation loss in peripheral neuropathy (DM, ETOH)
- Loss in either suggests posterior column disease (Vit B12 deficiency)
sensory exam: posterior columns
discriminative sensations
- stereognosis
- graphesthesia
- 2 point discrimination
- Point localization
- extinction
stereognosis
testing for recognition of something in your hand without seeing it (finding phone in purse without seeing it)
graphesthesia
write something in the patients hand
2 point discrimination
- using a one or two pronged tool
- being able to determine if what is touching the patients finger is one or two points
point localization
Eyes closed, touch patient; have them open their eyes and touch themselves where you touched them
extinction
Eyes closed, touch patient with simultaneous stimulation; ask where patient felt touch (should be both)
tests for balance and coordination
Tests motor system, cerebellar system, vestibular system and sensory system
- Rapid alternating movements
- Point-to-point movements
- Gait
- Stance
Rapid Alternating Movements
- Flip hands back and forth on thighs
- Tap index finger on thumb
- Tap foot quickly
- These test for dysdiadochokinesis (cerebellar disease)
point to point movements
- Ask pt to touch your index finger and then his/her nose alternately; watch for smooth movements
- Hold your finger in one place and have patient raise their arm, then lower their arm to touch your finger
- Heel-to-shin, note smoothness and accuracy
gait
- Ask patient to walk across room to observe balance
- Walk heel-to-toe or Tandem walking
- Walk on the toes, then on the heels
- Hop in one place on one foot at a time
- Shallow knee bend
- Rise from sitting to standing position
stance
- romberg test
- pronator drift
romberg test
Ask pt to stand with feet together then have patient close eyes. Positive Romberg test is loss of balance.
pronator drift
Stand with both arms stretched out forward with palms up (supination), then close eyes. Positive Pronator Drift when one arm drifts down and starts to pronate.
ankle clonus
- Next step if pt’s reflexes are hyperactive
- Support knee in partially flexed position
- Gently dorsiflex and plantarflex foot to relax it
- Sharply dorsiflex foot and hold
Anal reflex
- Stroke of four quadrants of anus with dull object
- Normally contraction of anal musculature occurs
- Loss of anal reflex suggests lesion in cauda equina area
astereognosis
inability to recognize objects placed in the hand
hypotonia
decreased muscle tone
hypertonia
increased muscle tone
spasticity
- increased resistance that varies
- commonly worse at the stremes of range
paresis
weakness (imparied strength)
plegia
paralysis
ataxia
gait that lacks coordination
clonus
rhythmic jerking from flexion to extension in response to muscle stimulation
dysarthria
impaired speech due to uncoordination of speech muscles
dysdiadochokinesis
when one movement cannot be followed quickly by its opposit - movements are slow, irregular or clumsy
