The Voluntary Motor SystemExamination

Joseph S. Ferezy, D.C.© 1999 All Rights Reserved

Motor Function Is Assessed Through Muscle Testing. Strength Tone Volume

Basic Concepts Of Motor System Innervation Voluntary Motor

Impulses Are Initiated In The Motor Cortex

Each Area Of This Cortex Controls An Area Of The Face And Body

Motor Homunculus No Rigid

Organization Brain Plasticity Is

Considerable. General Principles Of

TopicalLocalization Of Brain Function Remain Unchanged.

Motor Cortex Neurons Control Cranial Nerves

Via Corticobulbar Tract To Lower Motor Neurons In Brainstem Nuclei.

Descend Along Corticospinal Path, Through Brainstem Down Spinal Cord To Synapse On LMN’s In Anterior Horn.

General Inspection And Palpation Every Good Evaluation Begins With

Inspection. Muscle Inspection Must Be Performed

With The Examined Areas Disrobed. Inspection Of Body Contours With The

Patient In The Standing Neutral Posture. Systematically Check For Atrophy Or

Hypertrophy.

Observe For Muscle Fasciculation. Discrete, Palpable Contractions Of Small Areas

Of Muscle. May Or May Not Be Felt By The Patient. Bag Of Worms. More Apparent After Gently Percussing Over

The Muscle. Due To Spontaneous Discharges Along Neurons,

Causing Contraction Of All Muscle Fibers Innervated By That Neuron.

Muscle Strength Testing Strength Of Muscles Gives Direct

Information About Nerve Integrity. Examiner Has Idea As To What Is Normal

Amount Of Strength For A Particular Sex, Age, And Build.

Right Versus Left Side Strength Is Invaluable.

Accepted Rules For Strength Testing Expected Strength Of

Patient's Muscle Matched By Your Own.

Use Laws Of Muscle Strength And Mechanical Advantage To Match Or Exceed The Patient'sStrength.

Patient Exerts Maximal Effort.

Muscle's Strength Increases As Its Length Decreases.

Muscle Strength Body Part Passively Placed Midway Between

Flexion And Extension. “Resist My Effort To Move Your (Arm, Leg, Etc.).” Exert Power In A Slow Crescendo, Until You Begin

To Defeat The Patient's Effort. Test The Opposite Side Immediately Following. Smooth, Weakened Resistance Throughout The

Range Of That Muscle's "Give-way" Muscle Weakness, Noted In Non-

organic Weakness.

Antigravity Muscles Those Muscles That Hold

The Body Up Against Gravity

Stronger Than Their Antagonists.

Wrist Flexors Are Stronger Than Wrist Extensors

Triceps Stronger Than The Biceps

Trunk Extensors Stronger Than Flexors

Plantar Flexors Stronger Than Dorsiflexors.

Develop An Organized TestingMethod

Muscles To Test

More Muscles To Test

Abdominal Muscles Partial Paralysis (Paresis) Use Umbilical

Migration Test Supine Patient Is Asked To Per-

Form A Partial Sit-up. Normally, The Umbilicus

Does Not Move With Paresis Or Paralysis, The

Umbilicus Will Migrate Toward The Side Of The Stronger Muscles (Beevor's Sign).

Drift Patient Asked To Extend Both Arms, Hands

Supinated, Eyes Closed. Failure To Maintain This Position May Be Due

To A Unilateral Upper Motor Neuron Lesion Pronation And Lateral Dropping Or Drifting Of One

Extremity.

In Cerebellar Disease, The Ipsilateral Extremity Drifts Laterally.

Recording Muscle Strength Document Normality, As

Well As Progress Or Deterioration Of A Particular Condition.

For Intra- And Interoffice Consistency, A Scale Of O To 5 Should Be Employed.

Noted As 0/5, 1/5, 2/5, 3/5, 4/5, Or 5/5.

Recording Muscle Strength 0/5 Signifies Complete Paralysis. 5/5 Muscle Strength Is Within Normal Limits. 1/5 Signifies Severe Paresis (Just A Twitch Of

Movement) 2/5 Movement Without Gravity 3/5 Movement Only Against Gravity 4/5 Mild Paresis That May Be

Described As Just Subnormal.

Percussion May Be Performed To Assess Primary Muscle Or

Peripheral Nerve Disease. Performed By Directly Striking The Belly Of A

Muscle (Often The Thenar Eminence) With The Pointed End Of A Reflex Hammer

Note Percussion Irritability (Intrinsic Irritability) Focal Muscle Contraction Appearing As A Slight Transient Ripple Or Dimple At

The Site Of Impact To The Muscle. Completely Independent Of Any Volitional Or Reflex

Activity And Is Normal In Many Individuals.

Percussion Cannon's Law Of Hyperexcitability Of

Denervated Structures. Muscle Percussion Irritability May Be

Greatly Increased In Denervated Muscles.

Percussion Percussion Myoedema.

Hump Or Bump At The Site Of Percussion. Usually Associated With Debilitation, Uremia, Or Myxedema.

Percussion Myotonia Signifies A Myopathy Palm Is Placed Upward On A Table. After Percussion Of The Thenar Eminence, The Thumb May

Actually Rise Off Of TheTable Due To Contraction Of The Thenar Muscles.

May Be Performed On The Tongue By Placing A Tongue Blade Under The Tongue And Per cussing It With The Reflex Hammer.

If The Tongue Mounds Up, It May Indicate Myotonia.

Percussion Myotonia Myotonia May Also Be Assessed By Asking

ThePatient To Make A Tight Fist And Then Quickly Opening It On Command.

A Delayed Relaxation May Indicate Myotonic Grip.

Muscle Tone Operationally Defined As The Muscular Resistance Felt By

An Examiner When Moving A Patient's Joint Without VoluntaryResistance.

Assessing It Is The Most Subtle If Not Difficult Task In Neurological Muscle Assessment.

Normal Resting Muscle Has Palpable (Albeit Minor) Tone. Segmental And Suprasegmental Reflexes. Inherent Muscular Elasticity. Characterized As Normal, Increased, Or Decreased. Increased Paraspinal Muscle Tone Is Common But Rarely

Pathological.

Hypertonia Two Types Spasticity And Rigidity

Spasticity Increased Muscular Resistance Felt By The Examiner

During Quick Joint Motion, Which Then Rapidly Fades Away.

"Clasp-knife“ Interruption In The Pyramidal Pathways Is Responsible Degree Of Spasticity Is Often Roughly Proportional To The

Degree Of Hyperreflexia And Muscle Clonus. Attempt To Move Two Or Three Joints In An Erratic And

Unpredictable Fashion, To Avoid A Patient's Inadvertent “Help" In Moving The Body Part For You.

Spas.gl

Rigidity Muscular Resistance Felt When Moving A Resting Joint,

Which Persists As The Joint Is Moved Through Its Entire Range Of Motion.

Consistent With Lesions Of The Extrapyramidal Pathways. May Be Related To Muscle Spindles Mechanism

Interference From Diseased Extra-pyramidal Structures. Performed In The Same Manner As The Test For Spasticity

Except That Brisk Stretch Is Unnecessary. All Ranges Of Motion Are Affected. All Body Muscles Are Involved. Mixtures Of Spasicity And Rigidity Are Common.

Hypotonia Indicative Of Neurological Damage At The Level Of

The Reflex Arc Cerebellar Disease May Cause Diffuse Hypotonia. Lesions Of The Motor Nerve Cell Body In The Spinal

Cord, Ventral Root, Motor Nerve Axon, Neuromyal Junction, Or Even Of Effecters Of The Sensory Arc, Including The Sensory Axon, Nerve Cell Body, And Dorsal Root, Might Yield Hypotonia.

Primary Myopathies, Neural Shock, And Cerebellar Disease

Neural Shock A Phenomenon That Is In No Way Related To

Vascular Shock. Neural Shock May Occur Following Acute,

Severe Upper Motor Neuron Damage, In Either The Brain (Cerebral Shock)Or The Spinal Cord (Spinal Shock Or Diashesis).

First Causes Only Peripheral Type Neurological Findings.

Neurological Signs Deficit Phenomena.

A Loss Of Normal Neurological Function. Reductions In Muscle

Tone Stretch Reflexes Strength Volume

LMN Lesions Produce Only Deficit Phenomena.   

Exaggerations Or Perversions Of Normal Neuro Function

Due To A Loss Of Cortical Inhibition. Hyper-reflexia Hypertonia Pathological Reflexes

Only Associated With Central Nervous System Motor Lesions, Which May Produce Both Deficit And Release Phenomena.

Involuntary Movements (Dyskinesias) Many Actions Have Both Voluntary And Involuntary

Components Posture Breathing Sphincter Action Etc.

Certain Individuals Possess Greater Ability To Control Voluntary And Even So-called Involuntary Muscular Actions.

Those Movements That The Patient Cannot Start Or Stop At The Doctor's Command.

May Be Caused By A Structural Or Biochemical Nervous System Lesion.

Involuntary Movements Diagnosis

Evolution When Movements Appear Or Disappear What (If Anything) Exacerbates Them.

Physical Findings Can Be Noted During The Physical/neurological Examination. Pattern Distribution Rate Amplitude Force

Most Movements Will Fall Into A Specific Category.

Involuntary Movements Some Are Actually Normal.

Physiological Tremor Alternating Contractions Of Agonists And Antagonists Variability Of The Degree Of Tremor Between Individuals

Is Great. Tremors Occur At Approximately 10 Hz. Physiological Synkinesias Are Involuntary But Normal

Movements Myoclonic Jerks Are Startle Reactions (May Be Seizure

Disorder). Benign Fasciculation's - Twitches Within A Muscle That

Often Occur After Exercise.

Pathological Involuntary Movements Pyramidal Disease And Spastic Postures. Extrapyramidal Disease Will Cause

Notable Slowing Of Movement Rigid And Excessive Involuntary

Movements. Hyperkinesias And Hypokinesias.

Dyskinesia’s Hypokinesia Decreased Movement

Depression Parkinsonism.

Hyperkinesia Increased Movement;

Exacerbated By Emotional Stress, And All Decrease With Repose. Patients Can Also SufferFrom Any Combination Of The Listed Conditions.

Tremor Emotional: A Rapid Tremor Of Low Amplitude

That Worsens With Volitional Movements. Familial: A Hereditary Tremor That Usually

Affects The Hands. Senile: Similar In Character To Familial Tremor,

And Associated With Aging. Parkinsonian: A "Pill-rolling“ Movement Of The

Hands Seen When They Are At Rest That Disappears Or Damps Down During Volitional Movement.

Tremors Nontremorous Hyperkinesia Or Chorea: Random,

Quick Movements Simulating Fragments Of Normal Movements (Fidgets).

Athetosis: Slow, Writhing Movements Of The Fingers And Extremities That May Come And Go And Are Usually Associated With Pyramid- Al Tract Signs.

Dystonia: Slow, Alternating Contraction And Relaxation Of Agonists And Antagonists.

Hemiballismus: A Violent, Hinging Movement Of Half Of The Body.

Tremors Tics: Quick, Stereotyped, Repetitive Movements Of The Face, Tongue, Or Extremities; Associated With Emotional Stress.

Akathisia: Motor Unrest Manifested As Continual Shifting Of Posture And/or Movements;Associated With Parkinson's Disease And Psychotropic Medication Use.

Epilepsy: Tonic Or Clonic Spasms Of All Or Part Of The Body. Tardive Dyskinesias And Other Medication Related Disorders

Largest Single Category Of Involuntary Movement. A Biochemical Lesion From Long-term Exposure To Certain Agents. Smacking Movements Of The Lips, Jaw, And Tongue.