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DCR TUTORIAL 5 - NEUROLOGICAL EXAM (MOTOR)
HISTORY – What in the history points to the need for a Motor exam?
Weakness, fall, dropping, tripping, fasciculation, involuntary movements.
OBSERVATION – Starts with your first sight/touch of the patient, how do they
move breathe, stand, talk etc. What aspects of their stance or gait might
suggest neuro-motor deficits?
Hemiballismus (violent movement), dystonia (contraction of antagonist),
tics, dyskinesia (tics in face), tremor (rhythmic movement), involuntary
movement, myoclonus (mm jurks), chorea, bradykinesia (slow movement).
TONUS & CLONUS – What is the definition of Tonus? How is it tested?
Tonus: A state of partial contraction present in a muscle in its passive state
(UMNL).
Test: Roll arms and legs, slide heals on the table.
What types of Hypertonia do you know? What about Hypotonia? What might
these imply?
Hypertonia: Abnormal increase in muscle tension and a reduced ability of
a muscle to stretch (UMNL).
Hypotonia: State of low muscle tone (the amount of tension or resistance
to movement in a muscle), often involving reduced muscle strength.
What is Clonus, how might you elicit it, what is implied by its presence?
Clonus: Series of involuntary, rhythmic, muscular contractions and
relaxations. Clonus is a sign of certain neurological conditions, particularly
associated with upper motor neuron lesions involving descending motor
pathways, and in many cases is, accompanied by spasticity (another form of
hyperexcitability).
Test: Clonus at the ankle is tested by rapidly flexing the foot into
dorsiflexion (upward), inducing a stretch to the gastrocnemius muscle.
Subsequent beating of the foot will result, however only a sustained clonus
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(5 beats or more) is considered abnormal. Clonus can also be tested in the
knees by rapidly pushing the patella (knee cap), towards the toes and the
wrist by holding on extention and forcing extension.
What is Hemiplegia ? Paraplegia? Quadraplegia?
Hemiplegia: Total paralysis of the arm, leg, and trunk on the same side of
the body.
Paraplegia: Impairment in motor or sensory function of the lower
extremities.
Quadraplegia: Paralysis of all four limbs. Also called tetraplegia.
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DEEP TENDON REFLEXES – How are these elicited? What responses might
be found and what is implied by them? What nerve root levels are being
tested in each reflex?
Testing the reflexes assesses the integrity of the reflex arc and the
supraspinal influence that affect it.
Mm
Level
Nerve
Biceps
C5/6
Musculocutaneous
nerve
Brachioradialis
C5/6
Radial nerve
Supinator
C5/6
Pronator
C6/7
Median nerve
Action
Normal
response
Elbow flexion
Elbow flexion
and
forarm
supination
Hold the patient’s Pronation
of
hand vertically so the the forearm
wrist is suspended.
From the medial side,
strike the distal end of
the radius directly with
a horizontal blow.
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Triceps
C6/7
or
C7/8
Radial nerve
Fingers jerk
Knee
Quadriceps reflex
C8
L2/3/4 Femoral nerve
Adductor reflex
L2/4
Obturator nerve
Hamstring reflex
L4/S2
Sciatic nerve
Ankle
Achilles reflex
L5/S2
Tibial nerve
Elbow
extension
Knee extension
At medial epicondyle
of femur, adductor
magnus att
Hip and knee flexed at
about 90 degrees and
slight ext. rot. Tap on
medial
hamstring
tendon
Thigh
adduction
Flexion of knee
and contraction
of medial mass
of hamstrings
Contraction of
gastrocnemius
and
plantarflexion
of the foot.
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What do you understand by the “Reflex Arc”? What element in the muscle
actually implements the reflex? Is the Golgi Tendon Organ involved?
What is an “Inverted Reflex”, and what might it indicate.
Reflex arc: Neural pathway that controls an action reflex. Most sensory
neurons do not pass directly into the brain, but synapse in the spinal cord.
This characteristic allows reflex actions to occur relatively quickly by
activating spinal motor neurons without the delay of routing signals
through the brain, although the brain will receive sensory input while the
reflex action occurs.
There are two types of reflex arc: autonomic reflex arc (affecting inner
organs) and somatic reflex arc (affecting muscles).
(Efferent neuron = LMN)
Absent stretch reflexes= lesion in the reflex arc itself.
Associated symptoms and signs usually make localization possible:
1. Absent reflexes and sensory loss in the distribution of the nerve
supplying the reflex: the lesion involves the afferent arc of the
reflex—either nerve or dorsal horn.
2. Absent reflex with paralysis, muscle atrophy, and fasciculations: the
lesion involves the efferent arc—anterior horn cells or efferent nerve,
or both.
Most common: Peripheral neuropathy. Muscle diseases do not produce a
disturbance of the stretch reflex unless the muscle is rendered too weak to
contract. This occasionally occurs in diseases such as polymyositis and
muscular dystrophy.
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Hyperactive stretch reflexes are seen when there is interruption of the
cortical supply to the lower motor neuron, an "upper motor neuron
lesion." The interruption can be anywhere above the segment of the reflex
arc. Analysis of associated findings enables localization of the lesion.
The stretch reflexes can provide excellent clues to the level of lesions along
the neuraxis. For example, if the biceps and brachioradialis reflexes are
normal, the triceps absent, and all lower reflexes (finger jerk, knee jerk,
ankle jerk) hyperactive, the lesion would be located at the C6–C7 level, the
level of the triceps reflex. The reflex arcs above (biceps, brachioradialis, jaw
jerk) are functioning normally, while the lower reflexes give evidence of
absence of upper motor neuron innervation.
Segmental Innervation of Stretch Reflexes.
The laterality of reflexes is also helpful. For example, if all the reflexes on
the left side of the body are hyperactive and those on the right side are
normal, then a lesion is interrupting the corticospinal pathways to that
side somewhere above the level of the highest reflex that is hyperactive.
Individual nerve and root lesions can be identified by using information
about the reflexes along with sensory and motor findings.
The reflex arc is broken if any one of its elements malfunctions. The
physical sign of an interrupted reflex arc is a diminished or absent reflex.
When the descending motor pathway (the pyramidal tract) in the spinal
cord is injured above the level of the reflex arc, normal cortical inhibition
is lost, producing a hyperactive or spastic reflex.
0, 0
1, +
2, + +
3, + + +
4, + + + +
No response
Detectable only with reenforcement
Easily detectable
Brisk with at most a few beats of clonus
Sustained clonus
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SUPERFICIAL REFLEXES – What superficial reflexes do you know? How
are they tested. What responses might you get and what do they mean?
Receptors organs in the skin rather than in mm fibers.
Lost in disease of the pyramidal tract.
Abdominal reflex (T5/12):
Reflex stimulated by the stroking of the abdomen around the umbilicus
that results in contraction of the abdominal muscles; typically the
umbilicus moves towards the source of the stimulation.
The afferent is cutaneous sensory (tickle and light touch) that is
dermatomal and the efferent limb is the segmental innervation of the
abdominal muscles.
The reflex is typically lost in upper motor neurone syndromes.
This reflex is also lost due to a variety of causes, including age, abdominal
surgery, obesity, pregnancy and in parous woman.
Plantar response (L4/S2):
Reflex elicited when the sole of the foot is stimulated with a blunt
instrument. The reflex can take one of two forms. In normal adults the
plantar reflex causes a downward response of the hallux (flexion). An
upward response (extension) of the hallux is known as Babinski response.
The presence of the Babinski sign can identify disease of the spinal cord
and brain in adults (Pyramidal lesion), and also exists as a primitive reflex
in infants.
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POWER – How do you test power? Do you know the nerve root levels for the
muscles you commonly test? What are potential causes of muscle weakness?
What is fasciculation and when might it be encountered? Can you state a
common “pattern” of weakness and what it implies? Compare signs of Upper
and Lower Motor Neurone lesions.
C1-2 – Head flexion
C2-3- Shoulder shrug
C5 – Shoulder extension
C6 – Arm flexion
- Biceps
C7 – Arm extension
- Triceps
C8 – Wrist extensors
T1 – Hand grasp
L2 – Hip flexion
- Iliopsoas
L3 – Knee extension - L4 – Knee flexion
- hamstrigs
L5 – Ankle dorsiflexon
- Tibialis ant.
S1 – Ankle plantar flexion - Gastrocs
Causes of mm weakness:
Muscle weakness is a decrease in muscle strength, and it can be caused by a
neurologic, muscular or metabolic disorder. Neurologic disorders causing
muscle weakness include amyotrophic lateral sclerosis (ALS, also known
as Lou Gehrig’s disease), Guillain-Barre syndrome (an autoimmune nerve
disorder), stroke, or even a pinched nerve.
Muscular disorders, such as muscular dystrophy and dermatomyositis, are
also common causes of muscular weakness. Metabolic conditions that can
lead to weakness include Addison’s disease, low sodium or potassium
levels, and hyperparathyroidism. Ingestion of toxic substance, such as
insecticides, nerve gas, or paralytic shellfish poisoning, can cause muscle or
nerve damage along with muscle weakness. Muscle weakness can also result
from blood disorders, such as anemia and low blood sugar (hypoglycemia).
Grading of muscle strength (oxford scale)
Grade 0: No muscle movement
Grade 1: Muscle movement without joint motion
Grade 2: Moves with gravity eliminated
Grade 3: Moves against gravity but not resistance
Grade 4: Moves against gravity and light resistance
Grade 5: Normal strength
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Fasciculation:
Small, local, involuntary muscle contraction and relaxation which may be
visible under the skin or detected in deeper areas by EMG testing. They
arise as a result of spontaneous depolarization of a lower motor neuron
leading to the synchronous contraction of all of the skeletal muscle fibers
within a single motor unit. Fasciculations can happen in any skeletal
muscle in the body. Fasciculations have a variety of causes, the majority of
which are benign, but can also be due to disease of the motor neurons.
Fasciculations are commonly encountered in healthy people and are rarely
bothersome. In some cases the presence of fasciculations can be annoying
and interfere with quality of life. In such cases, where the remainder of the
neurological exam is normal, and EMG testing does not indicate any
additional pathology a diagnosis of benign fasciculation syndrome is
usually made.
UMN
Spastic paralysis
No wasting
No fasciculation
Brisk reflexes
Clonus
Extensor palmar
response (Babinski)
LMN
Flaccid paralysis
Mm Wasting
Fasciculation present
Reduced or absent reflexes
No clonus
Plantar response flexor
or absent
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CO-ORDINATION – What area of the brain is mostly involved in coordination?
What are commonly used tests for co-ordination? What findings indicate
abnormality? What is Ataxia? Why should you test joint position sense before
testing co-ordination? What is a pendular reflex and what does it indicate?
Cerebellum- Cerebellar dysfunctions
Motor coordination is the combination of body movements created with
the kinematic (such as spatial direction) and kinetic (force) parameters that
result in intended actions. Motor coordination is achieved when
subsequent parts of the same movement, or the movements of several
limbs or body parts are combined in a manner that is well timed, smooth,
and efficient with respect to the intended goal. This involves the
integration of proprioceptive information detailing the position and
movement of the musculoskeletal system with the neural processes in the
brain and spinal cord which control, plan, and relay motor commands.
The cerebellum plays a critical role in this neural control of movement
and damage to this part of the brain or its connecting structures and
pathways results in impairment of coordination, known as ataxia.
Pendular reflex: An abnormal response to a stimulus applied to the sensory
components of the nervous system. This may take the form of increased,
decreased, or absent reflexes.
Tests: Alternate heel to knee and heel to toe
Alternate nose to finger
Heel to shin
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STANCE & GAIT – What type of gait abnormalities can you list? What
underlying conditions might be responsible? Describe Romberg’s test? What
is being tested?
Gait abnormalities
Hemiballismus
Definitions
Very rare movement
disorder.
Involuntary flinging
motions of the
extremities.
Dystonia
Sustained muscle
contractions cause
twisting and repetitive
movements or
abnormal postures.
Tics
A sudden, repetitive,
nonrhythmic motor
movement or
vocalization involving
discrete muscle groups.
Movement disorder
which consists of
effects including
diminished voluntary
movements and the
presence of involuntary
movements, similar to
tics or chorea.
rhythmic movement
Dyskinesia
Tremor
Involuntary movement
Myoclonus
Chorea
mm jurks
Bradykinesia
slow movement
Underlying conditions
Structural brain lesions
but can occur with
metabolic
abnormalities e.g.
strokes, brain injury,
neoplasm…
May be hereditary or
caused by other factors
such as birth-related or
other physical trauma,
infection, poisoning
(e.g., lead poisoning) or
reaction to
pharmaceutical drugs,
particularly
neuroleptics.
????
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