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S4 L3: Motor System Examination by Dr. Morante

OUTLINE

Upper Motor Neurons (UMNs)part of the Central Nervous System (CNS)composed of neurons whose cells bodies are located in the brainor spinal cord

Lower Motor Neurons (LMNs)parrt of the Peripheral Nervous System (PNS)made up of motor and sensory neurons with cell bodies locatedoutside of the brain and spinal cord

PNS travel to and from the periphery, connecting the organs of actionwith the CNS.

EfferentsNerves which carry impulses away from the CNS

Afferentsbring signals towards the CNS

Spinal nerve rootsbundles of axons that contain both afferent and efferent nerveswhich enter and exit the spinal cord at any given level andgenerally connect to the same distal anatomic area

Neuroforaminapaired openings that allow for their passage out of the bonyprotection provided by the vertebral column where the nerve roexit/enter the spinal cord

Transmission of Signals from the Motor Cortex to the Muscles:

a. Voluntary movement begins withan impulse generated by the cellbodies in the cortex

b. Motor signals are transmitted directly from the cortex to the spinal cothrough the corticospinal tract

c. Indirectsignals are also relayed through multiple accessory pathwaysthat involve the following structures

Basal ganglia Cerebellum B

rainstem nuclei

Note: In general, the direct pathwaysare concerned more withdiscrete and detailed movements, especially of thedistal segments of the limbs, particularly the hands andfingers.

INTRODUCTION

I. IntroductionII. Motor Examination

A. InpectionB. PalpationC. Muscle Synmmetry andBulkD. Muscle ToneE. Manual Motor Testing

1. Major Muscle Groups2. Intrinsic Muscle of Hand3. Flexor of Fingers4. Wrist Flexion5. Wrist Extension6. Elbow Flexion7. Elbow Extension8. Shoulder adduction9. Shoulder abduction

10. Hip Flexion11. Hip Extension12. Hip Abduction13. Hip Adduction14. Knee Extension15. Knee Flexion16. Ankle dorsiflexion17. Ankle plantar flexion

III. Assessment A. Muscle Strength GradingB. Alternative GradingC. Pathologic FindingD. Peripheral nerves

IV. Gait Testing A. Station TestingB. Cerebellar / Coordination Testing

N i n a I a n J o h n G R a c h e l M a r k I v z J o b e J o c e l l e E d o G i e n a h J h o K a t h A y n z J e G l a d N i c k i e R i c o b e a r T e a c h e r D a d a n g N i a A r l e n e V i v s P a u l F . R i c o F . R e n M a i R e v s M a v i s J e p a y Y a n a M a y i S e r g e H u n g T o p e

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Corticospinal tractpyramidal tract

most important output pathway from the motor cortex30% originates from primary motor cortex

giant pyramidal cells or Betz cells30% from premotor cortex and supplementary motor areas40% from somatosensory areas

Pathway:

a. Cortex then through the posterior limb of the internal capsuleb. Brainstem forming the pyramids of the medullac. The majority of the pyramidal fibers cross the lower medulla to the

opposite side and descend into the lateral corticospinal tracts of the spinal cord

Terminates on the interneurons in the intermediate regionsof the spinal cord gray matter

Some fibers relay neurons in the dorsal horn Very few fibers terminate directly on the anterior motor

neurons that cause muscle contractiond. A few fibersdo not cross to the opposite side of the medulla but

pass ipsilaterally down the cord in the ventral (anterior)

corticospinal tractse. Many if not most of the fibers eventually cross to the opposite sideof the spinal cord either in the neck or in the thoracic region.

f. These fibers may be concerned with the control of bilateralmovements by the supplementary motor cortex.

Normal motor function depends on intact upper and lower motor neurons, sensory pathways and input from a number of other neurological systems.

Disorders of movement can be caused by problems at any point withinthis interconnected system.

INSPECTION

Normal Findings: No muscle movement when the limb is at rest.

Pathologic Findings:

a. TremorsSpecific type of continuous, involuntary muscle activity thatresults in limb movement,

Parkisonian resting tremor of the hand (the head and other body parts can also be affected) that diminisheswhen the patient voluntarily moves the affectedlimb.

Metabolic Cerebellar Essential rubral Physiologic tremor Tremor of Hepatic encelopathy

Benign Essential Tr emor Persists throughout movement and is not

associated with any other neurologicalfindings, easily distinguishing it from PD.

b. Dystoniac. Seizuresd. Involuntary movements

Chorea

Tardive dyskinesia Athetosis Pseudoathetosis Choreoathetosis Ballism

e. Clonus/myoclonusf. Spasm

Muscle cramps Oculogyric crisis Hemifacial cramps Palatal myoclonus Nystagmus B

lepharospasm Hiccup

g. Amyotrophic Lateral SclerosisResults in death of the lower motor neuron and subsequendenervation of the muscle.causes twitching of the fibers known as fasciculations, whcan be seen on gross inspection of affected muscles.

PALPATION

The major muscle groups to be palpated include:

a. Bicepsb. Tricepsc. Deltoidsd. Quadricepse. Hamstrings

Palpation should not elicit pain.

Assessment of Muscle Symmetry and MuscleBulk

Somewhat subjective and quite dependent on the age, sex and the

activity or fitness level of the individual.

Example: A frail elderly personwill have less muscle bulk then a 25 year

body builder.

Should be appropriately developed, after making allowances for thepatients age, sex, and activity level.Some allowance must be made for handedness

M OTOR EXA M INATION

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Pro cedure :

a. Patie nt shou ld be in a go wn so that the are as o f intere st are e xpo sed .

b. Care f u llye xamine the major mu scle grou ps o f the u pper and lo wer e xtre mitie s.

c. Mu scle grou ps shou ld appe ar symme tr icallyde ve lo ped whe nco mpared with the ir cou nter par ts o n the o ther side o f the bod y.

d .

If there is asymme tr y, no te if it f o llo ws a par ticu lar patter ne . Asse ss and co mpare the bu lko f u pper and lo wer e xtre mitie sf. Asse ss if ano ther pro ce ss (su gge sted by histor y or o ther aspe cts

o f the e xam) has re su lted in limited mo ve me nt o f a par ticu lar limbg. Palpatio n o f the mu scle s will give you a se nse o f u nder lying

mass.h. Co mpare :

Left to Right Proximal vs. Distal

Patholog ic find ing s:

Peripheral or LMN in jury

Muscles lose their inn ervation s and become very atrophicwith asymmetry following a particular n erve d istribution .

Spin al cor d tran section Tran saction at the thoracic level may cause upper extremitymuscle bulk to ben ormal or even in creased d ue toin creased d epend en ce on arms for activity, mobility, etc.Muscles of the lower extremity will atrophyd ue to loss of inn ervation and subseque n t d isuse.

Fracture Broken leg that has recently been liberated from a cast will

appear markedly atrophic.

Atrophy Hands (assess and compare thenar eminence) Shoulders Thighs

Assessment of Muscle Tone

Pr oced ur e:

a. Ask patient tor elax the joint that is to be tested b. Car efully move the limb thr ough its nor mal r ange of motion, being

car eful not to maneuver it in any way that is uncomfor table or gener ates pain.

c. Flex and extend the patients finger s, wr ist, elbow, should er sd . Flex and extend the patients ankle and knee, hips

Nor mal find ings:

a. When a muscle gr oup is r elaxed , the examiner should be able toeasily manipulate the joint thr ough its nor malr ange of motion.

This movement should feel fluid

b. Normal muscle generates some resistance to movement when alimb is moved passively by an examiner

Small, continuous resistance to passive movement

Patholog ic find ing s:

a. Decreased (flaccid )occurs when the lower motor neuron is cut off from themuscles that it normally innervates

b. Flaccid ityComplete absence of tone.

c. Increased (spastic/rig id )Occur when the upper motor neuron no long er functions.

Affected limb is held in a flexed position and the examiner may be unable to move the joint.Seen most commonly following a stroke, which results in thd eath of the upper motor neuron cell bod y in the brain.

d . Increased tone (hypertonicity)results from muscle contraction.

e. Parkinsons Disease (PD)Causes increase d tone, g enerating a ratchet-like sensation(known as cog wheeling ) when the affected limbs arepassively moved .

f. Deg enerative jointd isease of the kneeMigh t cause limited rang e of motion, th ough tone sh ould stilbe normal.

MANUAL MOTOR TESTING

Streng th testing must take into account th e ag e, sex and fitness level oth e patient.

Example: A frail, elderly, bed bound patient may have muscle weakness

due to severe deconditioning and not to intrinsic neurologicaldisease.

Interpretation must also consider the expected strength of the musclegroup being tested.

The quadriceps group, for example, should be much more powerfulthan the Biceps.

Note: Disorders that do not directly affect the muscles, upper or lower motor neurons can still alter tone. This is adisorder of the Extra Pyramidal System (EPS). The EPS

normally contributes to initiation and smoothness of movement.

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

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P ro cedure :

a. Major Mu scle Grou ps In the screening examination, it is reasonable to check only

the major muscles or muscle groups. More detailed testing can be performed in the setting of

discrete/unexplained weakness.

b. Intrinsic muscles of the hand (C 8, T 1)

Muscle being tested: Interossei

Innerva tion: Ulnar nerve

Procedure: Ask the patient to spread their fingers apart against

resistance (abduction). Then squeeze them together, with your fingers placed in

between each of their digits (adduction). Test each hand separately

c. Flexors of the fingers (C 7, 8, T1)

Mu scle being tested: Flexor DigitorumProfundus

Innerva tion: Median (radial ) and Ulnar (medial ) Nerves

P r o cedu re: 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.

d. Wrist flexion (C 7, 8, T 1)

Mu scle being tested: Flexor carpi radialis Flexor carpi ulnaris

Innervat ion: Median nerve

Ulnar Nerves.P r o cedu re:

Have the patient try to flex their wrist as you provideresistance.

Test each hand separately.

e. Wrist extension (C 6, 7, 8)

Mu scl e being tested : Extensor Radialis muscles

Innervation: Radial Nerve

P r o cedu re: Have the patient try to extend their wrist as you provide

resistance.

Note: Damage to the radial nerve results in wrist drop (loss of ability to extend the hand at the wrist). The nerve can becompressed against the humerus for a prolonged periodof time(known as a Saturday Night Palsy).

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f. Elbow Flexion (C 5, 6)

Muscle being tested: Brachialis Muscle (along with theBiceps Muscle)

Innervation: Musculocutaneous Nerve

Procedure:

Have the patient bend their elbow to ninety degrees whilekeeping their palm directed upwards. Then direct them to flex their forearm while you provide

resistance.

g. Elbow Extension (C 7, 8)

Mu scle being tested : Triceps muscle

Inn ervat ion : Radial nerve

Procedure: Have the patient extend their elbow against resistance while

the arm is held out (abducted at the shoulder) from the bodyat ninety degrees

h. Shoulder Adduction (C5 thru T1)

Muscle being tested: Pectoralis Major through the Latissimus

Innervation: Lateral pectoral nerve Medial Pectoral nerve Thoracodorsal nerve

Procedure: Have the patient flex at the elbow while the arm is held ou

from the body at forty-five degrees. Then provide resistance as they try to further adduct at the

shoulder.

i. Shoulder Abduction (C 5, 6)

Muscle being tested: deltoid muscle

Innervation: axillary nerve

Procedure: Have the patient flex at the elbow while the arms is held o

from the body at forty-five degress. Then provide resistance as they try to further abduct at the

shoulder.

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j. Hip Flexion (L 2, 3, 4)

Mus cle being t est ed : Iliopsoas muscle

Inn erv at ion : femoral nerve

P rocedu re:

With the patient seated, place your hand on top of one thighand instruct the patient to lift the leg up from the table.

k. Hip Extension (L5, S1)

Muscle being tested: gluteus maximus,

Innervation: inferior gluteal nerve.

Procedure:

With the patient lying prone, direct the patient to lift their legoff the table against resistance.

l. Hip Abduction (L 4, 5, S1)

Muscle being tested: Gluteus maximus Gluteus medius (primarily) Gluteus minimus

Innervation: Superior gluteal nerve Inferior gluteal nerve

Procedure: Place your hands on the outside of either thigh Direct the patient to separate their legs against resistance.

m. Hip Adduction (L2, 3, 4)

Muscle being tested: Adductor longus Adductor brevis Adductor magnus Gracilis

Inne r v at ion : Obturator nerve

Procedure: Place your hands on the inner aspects of the thighs. Direct the patient to close their legs against resistance.

n. Knee Extension (L2, 3, 4)

Muscle being tested: quadriceps muscle group

Innervation: femoral nerve

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Procedure: Have the seated patient steadily press their lower extremity

into your hand against resistance.

o. Knee flexion (L5, S1, 2)

Muscle being tested: Hamstring muscle group

Innervation: Sciatic nerve

Procedure: Have the patient rest prone. Then have them pull their heel up and off the table against

resistance.

p. Ankle Dorsiflexion (L4, 5)

Mu scle being t est ed : tibialis anterior

Inner v ation: deep peroneal nerve

P rocedu re: Direct the patient to pull their toes upwards while you

provide resistance with your hand.

q. Ankle Plantar Flexion (S 1, S 2)

Muscle being tested:

Gastrocnemius soleus

Innervation: sciatic nerve

Procedure: Have the patient step on the gas while you provide

resistance.

Note: Plantar flexion and dorsiflexion can also be

assessed by asking the patient to walk on their toes (plantar flexion) and heels (dorsiflexion).

Note: The peroneal nerve is susceptible to injury at the pointwhere it crosses the head of the fibula (laterally, belowthe knee). If injured, the patient develops Foot Drop,an inability to dorsiflex the foot.

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Grading of mus cle strength :

Grade Des cri ption 0/5 No mo vement 1/5 Slight contra ctilit y but no joint motion 2/5 Mo vementat the joint , but not against gra vit y

3/5 Mo vement against gra vit y, but not against added resistan ce

4/5 Mo vement against resistan ce , but less than normal 5/5 Normal strength

According to Harrison : Mus cle Strength

Grade Des cri ption 0 No mo vement 1 Fli cker or tra ce of contra ction but no asso ciated

mo vement at a joint 2 Mo vement with gra vit y eliminated 3 Mo vement against gra vit y, but not against resistan ce 4- Mo vement against mild resistan ce 4 Mo vement against moderate resistan ce

4+ Mo vement against strong resistan ce 5 Full po wer

Alternati ve Terms for Mus cle Grading :

a . Paral ysis no mo vement

b. Se vere wea kness mo vement with gra vit y eliminated

c. Moderate wea kness

mo vement against gra vit y but not against mild resistan ce d . Mild wea kness

mo vement against moderate resistan ce e . Full strength

Pathologi c findings :

a . Myositis rare condition chara cteri zed by idio pathi c mus cle inflammation that causes the patient to e xperien ce wea kness but not pain

b. Myo path yusuall y presents with pro ximal mus cle wea kness

c. Peri pheral neuro path yusuall y presents with distal wea kness

d . UMNd ysfun ction usuall y presents with pyramidal wea kness

Spe cial test for su btle wea kness :

Su btle wea kness can be hard to dete ct .Pa y attention to ho w the patient wal ks , uses and holds their arms and hands as the y enter the room , get u p and do wn from a seated position,mo ve onto the e xamination ta ble , et c.

Pronator driftTest for detecting slight weakness of the upper extremities

Procedure:

Ask the patient to stand for 20-30 seconds with both armsstraight forward, palms up, and eyes closed. Instruct the patient to keep the arms still while you tap the

briskly downward. The patient will not be able to maintain extension and

supination (and "drift into pronation) with upper motor neuron disease.

Common peripheral ner v es, inner v ation and clinical correlation:

PeripheralNer v e

SensoryInner v ation

Motor Inner v ation

SpinalNer v eRoots

ClinicalCorrelation

RadialNer v e

Back of thumb,index,

middle, and ring finger;

back of forearm

Wristextension

andabduction of

thumb inpalmer plane

C6, 7, 8 At risk for

compression ahumerus,known as

"Saturday NighPalsy

Ulnar Ner v e Palmar anddorsal

aspects of pinky and of ring finger

Abduction of fingers

(intrinsicmuscles of

hand)

C7, 8and T1

At risk for injuwith elbowfracture.Can gettransient

symptoms

when inside oelbow is struck("funny bone"distribution)

MedianNer v e

Palmar aspect of the

thumb,index,

middle and ring finger;palm below

thesefingers.

Abduction of thumb

perpendicular to palm(thenar

muscles).

C8, T1 Compression acarpal tunnelcauses carpal

tunnelsyndrome

LateralCutaneousNer v e of

Thigh

.Lateral

aspect thighL1, 2

Can becomecompressed inobese patients,

causingnumbness ov erits distribution

Peroneal Lateral leg,top of foot

Dorsiflexionof foot(tibialisanterior muscle)

L4, 5; S1Can be injuredwith proximafibula fractureleading to foo

drop (inability dorsiflex foot

Note: The largest and most powerful groups are those of thequadriceps and hamstrings of the upper leg

ASSESS M ENT

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Ability to stand and walk normally is dependent on input from severalsystems, including:

Visual Vestibular Cerebellar Motor system

Sensory systemThe precise cause(s) of the dysfunction can be determined byidentifying which aspect of gait is abnormal and incorporating thisinformation with that obtained during the rest of the exam.

P rocedure: Walk across the room, turn and come back Walk heel-to-toe in a straight line Walk on their toes in a straight line Walk on their heels in a straight line Hop in place on each foot Do a shallow knee bend Rise from a sitting position

P ath ol ogic find ings:

P arkinsons Disease Difficulty getting out a chair and initiating movement

C erebellar disorder Patient presents with lack of balance and a wide based gait

STATION TESTING

a. Equilibratory testing(balance testwith romberg test)

Procedure: Have the patient stand in one place. This is the test for balance incorporating input from the visual,

cerebellar, proprioceptive, and vestibular systems. If they are able to do this, have them close their eyes, removing

visual input (Romberg test) Ask the patient to stand from a chair, walk across the room, turn,

and come back towards you.

b. Heel to toe walking (tandem gait)

P rocedure: Ask the patient to walk in a straight line, putting the heel of one

foot directly in front of the toe of the other. This also a test of balance. This may be difficult for older patients (due to the frequent

coexistence of other medical conditions) even in the absence of neurological disease.

Assess the following:

a. Difficulty getting up from a chair Assess ease of rising from a sitting position Problems with this activity might suggest proximal muscle

weakness, a balance problem, or difficulty initiatingmovements.

b. Balance Assess if they veer off to a particular side

c. Rate of walking Assess how fast or how slow they move during walking Are they slow moving secondary to pain/limited range of

motion in their joints, as might occur with degenerative jdisease or due to Parkinsons disease?

d. Attitude of Arms and Legs Assess loss of movement and evidence of contractures

(example:post-stroke)? Assess movement of arms and legs. Look for presence of arm swing during walking

e. Heel to Toe Walking Ask the patient to walk in a straight line, putting the heel o

one foot directly in front of the toe of the other. referred to as tandem gait a test of balance may be difficult for older patients (due to the frequen

coexistence of other medical conditions) even in theabsence of neurological disease.

P athologic findings:

a. Loss of balance suggests impaired proprioception.

b. P arkinsons Disease Movement start off slow and then accelerate, perhaps losin

control of their balance or speed

c. Cerebellar ataxia Balance impairment is not ameliorated by visual orientatio

In cerebellar lateral lobe lesion falling is toward the affected side In frontal lobe lesion

falling is to the opposite side In lesion at the midline or vermis

falling indiscriminately Lesion on both hemispheres

generalized loss of balance

COORDINATION/ CEREBELLAR TESTING

The cerebellum fine tunes motor activity and assists with balance.

Dysfunction results in a loss of coordination and problems with gait.The left cerebellar hemisphere controls the left side of the body andvice versa.For the screening exam, using one modality will suffice.

If an abnormality is suspected or identified, multiple tests should bedone to determine whether the finding is durable.

Note: If the abnormality on one test is truly due to cerebellar dysfunction, other tests should identify the sameproblem. Gait testing is an important part of thecerebellar exam.

G AIT TESTIN G

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