Lecture 2: Neurologic Asssessment Flashcards
Learning Objectivess
- Describe the structure and the function of the central and peripheral nervous system
- Discuss risk factors associated with a cerebral vascular accident (CVA) commonly known as stroke
- Perform a physical assessment of the neurologic system using the correct techniques
- Differentiate between normal and abnormal findings of the neurologic system
Central Nervous System CNS
brain and spinal cord
Peripheral Nervous System (PNS)
all the nerve fibers existing outside the brain and spinal cord
- 12 cranial nerves
- 31 pairs of spinal nerves and their branches (2 nerve roots)
either sensory (Afferent) or motor (Efferent)
“motors are Efficient”
Cerebral Cortex
- thought, memory, reasoning, sensation, and voluntary movement
Each half of cerebrum is a hemisphere
Each hemisphere divided into four lobes: frontal, parietal, temporal, and occipital
Frontal Lobe
- personality, behavior, emotions, and
*intellectual function
initiates voluntary movement
*Broca’s area: Motor speech
-Damage causes expressive aphasia (BROCen speech)
Parietal Lobe
sensation
Occipital Lobe
primary visual receptor
Temporal Lobe
*primary auditory reception center, taste, and smell
*Wernicke’s area: Language comprehension
-Damage causes receptive aphasia
What happens when the cerebral cortex is damaged
produces a corresponding loss of function:
Motor weakness
Paralysis
Loss of sensation
Impaired ability to understand and process language
Basal Ganglia
Large bands of gray matter in two cerebral hemispheres that form the extrapyramidal system
- Initiate and coordinate movement
Thalamus
Main relay station where sensory pathways of spinal cord, cerebellum, and brain stem form synapses
located in between the basal ganglia
Hypothalamus
Major respiratory center
appetite
sex drive
temperature
heart rate
blood pressure
sleep
anterior and posterior pituitary gland regulation
coordination of autonomic nervous system
Cerebellum
-located under occipital lobe
-coordination of voluntary movements, equilibrium, and muscle tone
-Does not initiate movement, but coordinates movements
*Coordinates many different muscles needed in playing piano, swimming, or juggling
Crossed Representation (decussation) in the pathways of the CNS
the crossing over of tracts such as the left and right cerebral cortex
L cortex: receives sensory information from and controls motor function to right side of the body
R cortex: receives sensory information from and controls motor function to left side of the body
Cerebrovascular Accident (CVA)
Stroke
the 5th leading COD
leading cause of disability
Blood flow to a portion of the brain is interrupted or stops, depriving the brain cells of oxygen. If blood flow is blocked for more than a few seconds, brain cells begin to die and permanent damage may result
Major risk factors- HTN (Silent Killer- importance of BP screenings), DM, Smoking
Stroke belt (dietary factors) NC, SC, GA, AL, MS, LA, AK, TN
if we can identify the risks, we can intervene more early in the process
F: facial Drooping
(smooth nasal labial fold)
A: arm Swaying
S: speech (garbled, slurred)
T: time to call 911
dizziness= most missed symptom
Sensory pathways
(how does sensation travel and what roots can it take)
sensation travels in Afferent fibers in peripheral nerves
>
through the posterior (dorsal) root
>
into the spinal cord
Can take one of 2 roots:
1. spinothalamic tract
2. posterior (dorsal) columns
Spinothalamic tract sensory pathway
pain, temperature, and crude or light touch
Posterior (dorsal) columns sensory pathway
position, vibration, finely localized touch
what are Motor Pathways and what tracts can messages take?
carry Efferent messages from the CNS to the muscles
- pyramidal (corticospinal) tract
*mediate skilled, discrete, voluntary momement (ie: writing) - Extrapyramidal tracts (motor nerve fibers outside the pyramidal tract)
*maintain muscle tone
*controls gross body movements such as walking - cerebellar system
*movement, equilibrium, posture
Reflexes
basic defense mechanisms of the nervous system
- Involuntary
- below level of conscious control
- permits quick reaction to potentially painful or damaging situations
Four types of reflexes:
*Deep tendon reflexes (DTRs)
*Superficial (i.e., corneal reflex)
*Visceral (i.e., pupillary response to light)
*Pathologic (i.e., Babinski’s)
What are the 4 types of reflexes
Deep tendon reflexes (DTRs)
Superficial (i.e., corneal reflex)
Visceral (i.e., pupillary response to light)
Pathologic (i.e., Babinski’s)
Reflex Arc
Tapping the tendon stretches the muscle spindles which:
- Activates afferent sensory fibers
- Travels to dorsal root
- Synapse in spinal cord with the motor neuron
- Motor efferent fibers leave via the ventral root
- Travel to the muscle
- Stimulates muscle contraction
Dermatomes (PNS)
general definition
Each area of body sensation is supplied by nerves at a specific level.
Overlapping and somewhat variable.
Compression of a nerve will lead to a pattern of loss specific to a dermatome.
Sensory changes often precede motor loss.
Useful Landmarks of Dermatomes
memorize
Thumb at C6
Middle finger at C7
Fifth finger at C8
Axilla at T1-T2
Nipple at T4
Umbilicus at T10
Groin in region of L1
Knee at L4
Cranial Nerves (PNS)
general definition
Enter and exit brain rather than spinal cord
*CN I and II extend from cerebrum
*CN III to XII extend from lower diencephalon and brain stem
12 pairs of cranial nerves supply primarily head and neck
*except vagus nerve, which travels to heart, respiratory muscles, stomach, and gallbladder
which cranial nerves are tested together and how
CNIII, CNIV, and CNVI
oculomotor, trochlear, and absucens
tested by “sky writing”
CNV of the PNS
Trigeminal
- motor: muscles of mastication
- sensory: Ophthalmic (forehead)
Maxillary (cheeks)
Mandibular (chin)
Overall Neuro Cranial Nerve Physical Exam Recap
1 smell
2 eyes
3. 3, 4 & 6 EOM
5 face sensation
7 puff cheeks, raise eyebrows
8 Ears – whisper
9 Say “ahhh”
10 Say “ahhh”
11 Shrug shoulders
12 Stick out tongue
Deep Tendon Reflexes: Biceps
C5 & C6 nerves innervates tendon
Elbow flexed at 45°.
With your thumb, press the biceps brachii tendon.
Strike your thumb with the reflex hammer.
Need to know normal reflex is contraction of biceps which causes visible or palpable flexion of elbow.
Checking the intactness of the reflex arc at specific spinal levels.
Deep Tendon Reflexes: Brachioradialis
C5 & C6
Strike brachioradialis tendon approximately 2-4 inches above base of the thumb over radius
Need to know reflex should cause slight wrist extension and/or radial deviation, supination and slight elbow flexion
Checking the intactness of the reflex arc at specific spinal levels.
Deep Tendon Reflexes: Triceps
C7 & C8
Relax the patient’s elbow in your hand at 90°.
Tap the triceps brachii tendon proximal to the olecranon process.
Need to know normal response is elbow extension.
Checking the intactness of the reflex arc at specific spinal levels.
Deep Tendon Reflexes: Achilles
S1
Have the patient sit on a table or bed so that legs dangle
Grasp the patient’s foot and pull it in dorsiflexion
Tap the tendon directly
Need to know normal response is contraction of the gastrocnemius and plantar flexion of the foot.
Checking the intactness of the reflex arc at specific spinal levels.
Need to know which nerve innervates tendon
Deep Tendon Reflexes: Grading
four point scale
0 No response
1+ Diminished, low normal
2+ Average, normal
3+ Brisker than average, possible disease
4+ Very brisk, hyperactive with clonus=disease
Deep Tendon Reflexes: Reinforcement
Ask person to perform isometric exercise in muscle group away from one being tested
-Causes muscles to contract and increase reflex activity
-Ask client to clench jaw for arm reflexes
-Ask client to the lock the fingers of both hands and pull them against each other for leg reflexes
Superficial Reflexes:
Babinski or Plantar reflex
L4-S2
With reflex hammer, draw a light stroke up lateral side of sole of foot and inward across ball of foot, like an upside-down “J”
- Normal response: plantar flexion of toes
- Abnormal response: dorsiflexion of big toe and fanning of all toes
- Positive Babinski is normal in infant up to 2 years
Pupillary Light Reflex procedure
Darken room
Ask person to gaze into distance
(this dilates pupils)
Advance a light in from side and note response
Normal:
* constriction of same-sided pupil (direct light reflex)
* simultaneous constriction of the other pupil (consensual light reflex)
Accommodation check procedure
Ask person to focus on a distant object
(This dilates pupils)
Have person shift gaze to near object, such as your finger held about 7 to 8 cm (3 inches) from nose
Normal response includes:
Pupillary constriction
Convergence of axes of eyes
