Medicine 2.3b Motor System Examination

CALDERON, GARCIA, HARDIN, MANABAT, SOLIS 1 of 8

MOTOR SYSTEM EXAMINATION

2.3-B August 11, 2014

PLM CM Dr. Guzman

Legend: normal text italics; red text

INTRODUCTION

TRANSMISSION OF SIGNALS FROM THE MOTOR CORTEX TO THE MUSCLES

2 Pathways for Motor Signals from Cortex to Spinal Cord: 1. DIRECT:

o Involves the corticospinal tract o Concerned more with discrete and detailed

movements, esp. of the distal segments of the limbs (esp. hands and fingers)

2. INDIRECT: involves the basal ganglia, cerebellum, and various nuclei of the brainstem

CORTICOSPINAL TRACT o Most important output pathway from the motor cortex o A.k.a the pyramidal tract because it forms the

pyramids of the medulla as it descends through the brainstem

o Majority of the fibers cross in the lower medulla to the opposite side, descending into the lateral corticospinal tract of the spinal cord

o Terminations: - interneurons in the intermediate regions of the

cord gray matter (mainly) - sensory relay neurons in the dorsal horn (few) - directly on the anterior motor neurons that cause

muscle contraction (very few) o A few of the fibers do not cross to the opposite side in

the medulla but pass ipsilaterally down the cord in the ventral corticospinal tracts (many fibers eventually cross) FXN: control of bilateral postural movements by the supplementary motor cortex

OVERVIEW OF THE EXAMINATION

Inspection and Palpation o Body position o Involuntary movements o Muscle bulk

MuscleTone

Manual Motor Testing

Coordination and Gait

testing.

If you see an abnormality, identify the muscle(s) involved.

Determine whether the abnormality is central or peripheral in origin, and begin to learn which nerves innervate the affected muscles.

EXAMINATION OF THE MOTOR SYSTEM

INSPECTION AND PALPATION

Body Positions

Observe during movement and at rest

Abnormal positions alert you to conditions such as mono- or hemi- paresis from stroke.

Involuntary Movements

Note location, quality, rate, rhythm, amplitude, their relation to posture, activity, fatigue, emotion, and other factors

For this part, we also consulted a journal in the following link: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2929378/; definitions lifted from it are in italicized red font. Kung gusto niyo lang naman

basahin

Tremors

Tremors are a specific type of continuous, involuntary muscle activity that results in limb movement.

o Parkinsonian o Metabolic o Cerebellar o Essential rubral o Physiologic tremor o Tremor of hepatic encephalopathy

Condition Characteristics

Resting tremor

when patient voluntarily moves affected limb

Head and other body parts can also be affected

Benign Essential Tremor

Tremor persists throughout movement

Not associated with any other neurological findings

rhythmic oscillatory movements divided into:

1. Resting (Static)Tremors o Most prominent at rest o May decrease or disappear with voluntary movement o Relatively slow, fine, pill-rolling tremor of

parkinsonism, about 5/sec 2. Postural (Action) Tremors

o Appear when the affected part is actively maintaining a posture

o Fine, rapid tremor of hyperthyroidism o Tremors of anxiety and fatigue, and benign essential

(and sometimes familial) tremor o Tremor may worsen somewhat with intention

3. Intention Tremors o Absent at rest o Appear with activity o Often get worse as the target is neared o Causes include disorders of cerebellar pathways, as

in multiple sclerosis

Oral-Facial Dyskinesias

A.k.a tardive (late) dyskinesias

Rhythmic, repetitive, bizarre movements that chiefly involve the face, mouth, jaw, and tongue grimacing, pursing of lips, protrusions of tongue, opening and closing of mouth, and deviations of jaw

Limbs and trunk involved less often

May be a late complication of psychotropic drugs such as phenothiazines, and have then been termed

Also occur in long standing psychoses, in some elderly individuals, and in some edentulous persons

Tics

Brief, repetitive, stereotyped, coordinated movements occurring at irregular intervals

Examples include repetitive winking, grimacing, and shoulder shrugging

Causes: o o Drugs (e.g. phenothiazines and amphetamines)

Dystonia

Dystonic movements are somewhat similar to athetoid movements, but often involve larger portions of the body, including the trunk.

Grotesque, twisted postures may result.

Causes include o drugs (e.g. phenothiazines) o primary torsion dystonia o spasmodic torticollis

Chorea

Repetitive, brief, irregular, somewhat rapid involuntary movements that start in one part of the body and move abruptly, unpredictably, and often continuously, to another part.

Choreiform movements are brief, rapid, jerky, irregular, and unpredictable

Occur at rest or interrupt normal coordinated movements

Unlike tics, they seldom repeat themselves

Face, head, lower arms, and hands: often involved

Causes o chorea (with rheumatic fever) o
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2929378/



2.3-B August 11, 2014

PLM CM Dr. Guzman

Athetosis

Slow, continuous, involuntary writhing movement that prevents maintenance of a stable posture.

Slower and more twisting and writhing than choreiform movements, and have a larger amplitude

Most commonly involve the face and the distal extremities

Often associated with spasticity

Causes include cerebral palsy

Pseudoathetosis

In adults, athetosis can be due to a severe distal sensory .

Choreoathetosis

Combination of chorea and athetosis

Most often caused by the dyskinetic form of cerebral palsy in which dystonia is a frequent associated movement disorder

Also associated with kernicterus and other causes of basal ganglia injury

Ballism

A type of chorea that affects proximal joints such as shoulder or hip. This leads to large-amplitude movements of the limbs, sometimes with a flinging or flailing quality.

Clonus/Myoclonus

Clonus o A series of involuntary, rhythmic, muscular

contractions and relaxations

Myoclonus: o Sudden, brief, rapid jerks, involving the trunk or limbs.

It is associated with a variety of disorders (also found in table of Generalized Seizures below).

o Sequence of repeated, often non-rhythmic, brief shock-like jerks due to sudden involuntary contraction or relaxation of one or more muscles.

o Distinguished from chorea by the fact that in myoclonus, all the movements are quick, whereas in chorea only some are.

Spasm

A sudden, involuntary contraction of a group of muscles o Muscle cramps o Oculogyric crisis o Hemifacial cramps o Blepharospasm o Palatal myoclonus or nystagmus o Hiccup

Seizure

I. PARTIAL SEIZURES

A. Simple Partial Seizures

Problem Clinical Manifestations

Postictal state

1a. With motor symptoms- Jacksonian

Tonic and then clonic movements that start unilaterally in the hand, foot, or face and spread to other body parts on the same side

Normal consciousness

1b. With motor symptoms- Other motor

Turning of the head and eyes to one side, or tonic and clonic movements of an arm or leg without the Jacksonian spread


2. With sensory symptoms

Numbness, tingling; simple visual, auditory, or olfactory hallucinations such as flashing lights, buzzing, or odors


3.With autonomic symptoms

epigastrium, nausea, pallor, flushing, lightheadedness


4. With psychiatric symptoms

Anxiety or fear; feelings of familiarity (dj vu) or unreality; dreamy states; fear or rage; flashback experiences; more complex hallucinations


B. Complex Partial Seizures

Clinical Manifestations Postictal state

The seizure may or may not start with the autonomic or psychic symptoms that are outlined above.

Consciousness is impaired and the person appears confused.

Automatisms: motor behaviors (chewing, smacking the lips, walking about, and unbuttoning clothes); and skilled behaviors such as driving a car

Pt may remember initial autonomic or psychic symptoms (which are then termed an aura), but is amnesic for the rest of the seizure.

Temporary confusion and headache may occur.

C. Partial Seizures that Become Generalized

Resemble tonic clonic seizures

Unfortunately, the patient may not recall the focal onset and observers may overlook it.

As in a tonic clonic seizure

Two attributes indicate a partial seizure that has become generalized: (1) the recollection of an aura, and (2) a unilateral neurologic deficit during the postictal period.

II. GENERALIZED SEIZURES

Problem Clinical Manifestations

Postictal state

A. Tonic Clonic Convulsion (grand mal)

Pt loses consciousness suddenly and body stiffens into tonic extensor rigidity

Breathing stops & pt becomes cyanotic

A clonic phase of rhythmic muscular contraction follows

Breathing resumes and is often noisy, with excessive salivation.

Injury, tongue biting, urinary incontinence may occur

Confusion, drowsiness, fatigue, headache, muscular aching, and temporary persistence of bilateral neurologic deficits (e.g. hyperactive reflexes and Babinski responses)

Pt has amnesia for the seizure; recalls no aura

B. Absence A sudden brief lapse of consciousness, with momentary blinking, staring, or movements of the lips and hands but no falling.

Two subtypes: 1. Petit mal absences

last less than 10 sec

2. Atypical absences more than 10 sec.

No aura recalled

In petit mal absences, a prompt return to normal; in atypical absences, some postictal confusion

C. Atonic Seizure, or Drop Attack

Sudden loss of consciousness with falling but no movements. Injury may occur.

Either a prompt return to normal or a brief period of confusion

D. Myoclonus sudden, brief, rapid jerks, involving the trunk or limbs.

Variable
http://en.wikipedia.org/wiki/Muscle_contraction



2.3-B August 11, 2014

PLM CM Dr. Guzman

III. PSEUDOSEIZURES

Problem Clinical Manifestations Postictal state

May mimic seizures but are due to a convention reaction (a

psychological disorder)

Movements may have personal symbolic significance and often do not follow a neuroanatomic pattern. Injury is uncommon.

Variable

MUSCLE BULK AND APPEARANCE

This assessment is somewhat subjective and quite dependent on the age, sex and the activity/fitness level of the individual.

ASSESSMENT:

The patient should be in a gown so that the areas of interest are exposed.

Using your eyes and hands, carefully examine the major muscle groups of the upper and lower extremities (e.g. biceps, triceps, deltoids, quadriceps, hamstring)

Palpation of the muscles will give you a sense of underlying mass.

Palpation should not elicit pain.

The largest and most powerful groups are those of the quadriceps and hamstrings of the upper leg (i.e. front and back of the thighs).

They should be symmetrical bilaterally

They should also be appropriately developed, after making sex, and activity level

^FIGURE: right leg is smaller than the left one

If there is asymmetry, note pattern. o Some allowance must be made for handedness (i.e.

right versus left hand dominance). o If it follows particular nerve distribution, this suggests

a peripheral motor neuron injury o Muscles which lose their lower motor innervation

become very atrophic.

Note similarity of bulk in the upper and lower extremities o Spinal cord transection at the Thoracic level will

cause upper extremity muscle bulk to be normal or even increased due to increased dependence on arms for activity, mobility, etc.

o However, the muscles of the lower extremity will atrophy due to loss of innervation and subsequent disuse.

Note other processes (i.e. during history) that has resulted in limited movement of a particular limb

o A broken leg that has recently been liberated from a cast will appear markedly atrophic

^FIGURE: Diffuse Muscle Wasting. Note loss muscle bulk in left hand due to peripheral denervation. Compare left and

right thenar eminences.

Muscular Atrophy: o Refers to a loss of muscle bulk, or wasting o Results from diseases of the peripheral nervous

system such as diabetic neuropathy, as well as diseases of the muscles themselves.

o Other causes of muscular atrophy include motor neuron diseases, diseases that affect the peripheral motor system projecting from spinal cord, rheumatoid arthritis, and protein-calorie malnutrition

o Process may be unilateral/ bilateral, proximal/distal o Pay attention to the hands, shoulders, and thighs o Thenar and hypothenar eminences should be full and

convex; spaces between the metacarpals should be full or only slightly depressed

o Atrophy of hand muscles may occur with normal aging

o Be alert for fasciculations. If absent, tap on the muscle with a reflex -hammer to try to stimulate them.

Hypertrophy: increase in bulk w/ proportionate strength

Pseudohypertrophy: increased in bulk but w/ diminished strength (seen in the Duchenne form of muscular dystrophy)

Abnormal Finding Associated Condition

Flattening of thenar & hypothenar eminences

Atrophy

Localized atrophy of thenar eminence

Median nerve damage

Localized atrophy of hypothenar eminence

Ulnar nerve damage

Fasciculations with atrophy & muscle weakness

Disease of peripheral motor unit

MANUAL MOTOR TESTING

Testing of motor and sensory function requires a basic understanding of normal anatomy and physiology. (see Transmission of Signals from Motor Cortex to Muscles above for brief pathway)

o Upper Motor Neurons (UMNs): part of the CNS; composed of neurons whose cell bodies are located in the brain or spinalcord

o Lower Motor Neurons (LMNs): part of the PNS; made up of motor and sensory neurons with cell bodies located outside of the brain and spinal cord. The axons of the PNS travel to and from the periphery, connecting the organs of action (e.g. muscles, sensory receptors) with the CNS.

o Spinal nerve roots: bundle of axons that exit and enter the spine at any given level and generally connect to the same distal anatomic area; contain both afferent and efferent nerves.

o Peripheral nerve: formed ultimately from contributions of several spinal nerve roots (efferents); follows a precise anatomic route on its way to innervating a specific muscle.

Normal motor function depends on intact UMN and LMN sensory pathways and input from other neurological systems problems at any point: disorders of movement



2.3-B August 11, 2014

PLM CM Dr. Guzman

There should be no muscle movement when the limb is at rest. Rare disorders (e.g. Amyotrophic Lateral Sclerosis) result in death of the lower motor neurons and subsequent denervation of the muscle causes twitching of the fibers known as fasciculations, which can be seen on gross inspection of affected muscles.

MUSCLE TONE

Slight residual tension maintained when a normal muscle with an intact nerve supply is relaxed voluntarily

ASSESSMENT:

Ask the pt to relax. If tense, may show inc. resistance.

While supporting the elbow, flex and extend the patient's fingers, wrist, and elbow, and put the shoulder through a moderate range of motion (ROM)

h with one hand, grasp the foot with the other, and flex and extend patient's ankle and knee.

There is normally a small, continuous resistance to passive movement.

Observe for decreased (flaccid) or increased (rigid/spastic) tone.

Be aware that many patients, particularly the elderly, often have other medical conditions that limit joint movement. Degenerative joint disease of the knee, for example, might cause limited ROM, though tone should still be normal.

If the patient has recently injured the area or are in pain, do not perform this aspect of the exam.

ABNORMALITIES

1. Increased resistance o If suspected, determine whether it varies as

you move the limb or whether it persists throughout the ROM and in both direction, for example, during both flexion and extension.

o Feel for any jerkiness in the resistance. 2. Decrease resistance

o Suggest diseases of peripheral nervous system, cerebellar disease, or acute stages of SC injury.

o If suspected hold the forearm and shake the hand loosely back and forth. Normally the hands moves back and forth freely but is not completely floppy.

3. Marked floppiness o Indicates hypotonia, flaccidity, or peripheral

motor system disorder.

DISORDERS OF MUSCLE TONE*

Spasticity: o Increased resistance that worsens at the extremes or

range that may occur when the UMN no longer functions.

o Rate dependent, increasing with rapid movement o Seen in Central corticospinal tract disease

Rigidity: o Increased resistance throughout the ROM and in both

directions o Not rate-dependent o Lead-pipe rigidity: increased resistance that persists

throughout a movement arc, independent of rate of movement

o Cogwheel rigidity: superimposed ratchetlike jerkiness with flexion and extension of the wrist or forearm

Flaccidity: Loss of muscle tone (hypotonia), causing the limb to be loose or floppy, hperextensible, or flail-like; occurs when the LMN is cut off from the muscles that it normally innervates.

Paratonia: sudden changes in tone with passive ROM o Mitgehen (moving with): sudden changes in tone with

passive ROM o Gegenhalten (holding against): sudden increase in

tone making motion more difficult

o Disorder of the Extra Pyramidal System (EPS). o The EPS normally contributes to initiation and

smoothness of movement. o PD causes tone generating a ratchet-like

sensation (known as cog wheeling) when the affected limbs are passively moved by the examiner.

* For Disorders that DO NOT DIRECTLY AFFECT the muscles, upper or lower motor neurons can still alter tone

MUSCLE STRENGTH

As with muscle bulk, strength testing must take into account the age, sex and fitness level of the patient

A frail, elderly, bed bound patient may have muscle weakness due to severe deconditioning and not to intrinsic neurological disease

Interpretation must also consider the expected strength of the muscle group being tested (ex. quadriceps > biceps)

Normal people vary widely in their strength, variables such as age, sex, and muscular training should be considered when setting a standard.

is usually slightly stronger than the nondominant side.

General Considerations in Testing Muscle Strength

Test muscle strength by asking the patient to actively resist your movement.

A muscle is strongest when shortest, and weakest when longest.

If the muscles are too weak to overcome resistance, test against gravity alone or with gravity eliminated.

o Ex. When the forearm rests in a pronated position dorsiflexion at the wrist can be tested against gravity alone.

o When the forearm is midway between pronation and supination extension at the wrist can be tested with gravity eliminated.

Finally, if the patient fails to move the body part, watch or feel for weak muscular contraction.

It is generally quite helpful to directly compare right vs left sided strength, as they should more or less be equivalent (dominant side > non-dominant).

If there is weakness, try to identify a pattern which might provide a clue as to the etiology of the observed decrease in strength. In particular, make note of differences between:

o Right vs Left o Proximal muscles vs distal o Upper extremities vs lower

If the weakness generalized, it is suggestive of a systemic neurological disorder or global deconditioning.

Condition Characteristics

Proximal weakness Suggestive of myopathy

Distal weakness Suggestive of peripheral neuropathy

Pyramidal weakness Suggestive of UMN dysfunction

Myositis (a rare condition characterized by idiopathic muscle inflammation) causes the patient to experience weakness but not pain.



2.3-B August 11, 2014

PLM CM Dr. Guzman

Grading of Muscle Strength

Grade Description

0/5 No muscle movement

1/5 Slight contractility but no joint motion

2/5 Movement at the joint, but not against gravity

3/5 Movement against gravity, but not against added resistance

4/5 Movement against resistance, but less than normal

5/5 Normal strength

Grade

Description

0/5 No muscle movement

1/5 Slight contractility but no joint motion

2/5 Movement at the joint, but not against gravity

3/5 Movement against gravity, but not against added resistance

4- Movement Against mild degree of resistance*

4/5 Movement against resistance, but less than normal Movement against moderate resistance*

4+ Movement against strong resistance*

5/5 Normal strength (full power)

Specifics of Muscle Strength Testing

Major Muscle Groups only

More detailed testing can be performed in the setting of discrete/unexplained weakness

When performing the strength test, always take into account the muscles involved, their corresponding innervation and their specific actions

Take note of the differences in male and female strength to avoid errors made by examiners due to subjectivity

Muscles Innervation Action

Interossei Ulnar nerve Adduction/abduction

of fingers

Flexor digitorum profundus

Median n. radial ; Ulnar n.

medial Finger flexion

Extensor radialis

Radial nerve Wrist extension

Brachialis Musculocutaneo

us nerve

Flexion and supination of the hand at the elbow

joint

Triceps brachii Radial nerve Extension of the

forearm

Pectoralis major

Lateral and medial pectoral

nerves Shoulder adduction

Deltoid Axillary nerve Shoulder abduction

Iliopsoas Femoral nerve Hip flexion

Gluteus maximus

Inferior gluteal nerve

Hip extension

Quadriceps femoris

Femoral nerve Knee extension

Hamstrings Sciatic nerve Knee flexion

Muscles at anterior

compartment of the leg

Deep peroneal nerve

Ankle dorsiflexion

Gastrocnemius and Soleus

Sciatic nerve Plantar flexion of

ankle

Test Procedure Picture Notes

Intrinsic muscles of the hand

(C 8, T 1 ulnar nerve)

Ask the patient to spread their fingers apart against resistance (abduction)

Squeeze them together, with your fingers placed in between each of their digits (adduction). Test each hand separately.

Weak finger abduction occurs in ulnar nerve disorders.

The muscles which control adduction and abduction of the fingers are called the Interossei, innervated by the Ulnar Nerve.

Test for Grip Flexors of the

fingers (C 7, 8, T1)

Ask the patient to make a fist, squeezing their hand around two of your fingers.

If the grip is normal, you will not be able to pull your fingers out. Test each hand separately.

A weak grip is seen in cervical radiculopathy, de

carpal tunnel syndrome, arthritis, and epicondylitis.

The Flexor Digitorum Profundus controls finger flexion and is innervated by the Median (radial ) and Ulnar (medial ) Nerves.

Test opposition of the thumb (C 8, T 1 median

nerve)

The patient should try to touch the tip of the little finger with the thumb, against your resistance.

Look for weak opposition of the thumb in median nerve disorders such as carpal tunnel syndrome

Medicine 2.3b Motor System Examination

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