Motor and Sensory Examination

Dr Rahul AwasthiNeurosurgery department

SAIMS

ASSESSMENT OF MOTOR SYSTEM :• INSPECTION AND PALPATION OF MUSCLES • ASSESSMENT OF TONES• EXAMINATION OF REFLEXES • TESTING MOVEMENT AND POWER • CO-ORDINATION

INSPECTION AND PALPATION OF MUSCLES

- Requires full exposure of muscles. - Look for asymmetry, inspecting both

proximally and distally. - Note any deformities. - Examine specially for wasting or hypertrophy,

fasciculation and involuntary movement.- Palpate muscles to assess their bulk.

Types of muscle wasting:

• Generalized wasting• Proximal muscle wasting• Distal muscle wasting

Common abnormalities • 1. Muscle bulk :• Lower motor neuron lesions cause wasting in

specific muscles.• Upper motor neuron damage can cause

disuse atrophy of muscle groups.• Certain occupation and sports leads to muscle

hypertrophy.• The wasting of muscle is associated with

diseases like rheumatoid arthritis, cachexia.

2.Fasciculation: Looks likes irregular twitches under the skin overlying muscles at rest commonly seen in LMN lesions.

3.Myclonic jerk: It is the sudden shock like contractions of one or more muscles. - Associated with epilepsy, diffuse brain damage and dementias .

4. Tremor: is oscillatory movement about a joint or a

group of joints resulting from alternating contraction and relaxation of muscles.

• Common Types i. Physiological tremor :- hyperthyroidism,

alcoholism.ii. Coarse tremor (slow) :-Parkinson's disease.iii. Intention tremor :- Cerebellar damage.

ASSESSMENT OF TONES

Tone: is the resistance felt by the examiner when moving

a joint passively through its range of movement.• Site to check the tone: • Upper Extremities - wrist and elbow joint • Lower Extremities - knee level, ankle joint.• Common abnormalities: Muscle tone may be

decreased (Hypotonia) or increased (hypertonia).

• Hypotonia : is decreased tone and usually associated with muscle

wasting, weakness and hyporeflexia.• Cause : breach in the reflex arc,cerebellar disease,

spinal shock.

• Hypertonia : There are two principal types hypertonia

1.Spasticity 2.Rigidity

Spasticity : means increased tone throughout range of motion, and then there is a sudden release (catch): so called ‘clasp knife effect ‘

• Seen in UMN lesion, pyramidal pathway lesion.• In second type, there is equal resistance in both

agonist and antagonists at any point: so called ‘ plastic or lead-pipe rigidity’.

• Seen in extra-pyramidal system.• Spasticity is velocity dependent(sudden release).

• Rigidity : increased tone throughout the range of motion.

• The agonist and antagonist contract alternately, rapidly : so called ‘cog-wheel rigidity’.

• seen in extra pyramidal diseases such as Parkinson’s disease.

• Rigidity is not velocity dependent (continuous) .

EXAMINATION OF REFLEXES

Reflexes 1.SUPERFICIAL REFLEXES 2. DEEP TENDON REFLEXES

SUPERFICIAL REFLEXES - elicited by striking skin or mucous membrane.

CREMASTERIC REFLEX(L1-2) :

• Abduct and externally rotate the patient's medial

aspect of the thigh.

• Stick the upper medial aspect of the thigh.

• Normally the testicle on the side stimulated will

rise briskly.

• Used to identify the level of spinal cord lesion

after injury.

• 2. DEEP TENDON REFLEXES :- Rapid muscle contraction response when deep receptors in the muscle or in the tendons are stimulated.

• 1. Hoffman's Reflex : - The test involves tapping the nail or flicking the terminal phalanx of the middle or ring finger.

• A positive response is seen with flexion of the terminal phalanx of the thumb

• 2. Finger jerk : - Place your middle and index fingers across the palmer surface of patient's proximal phalanges. - Observe the flexion of the patient's finger

Biceps jerk (C5-C6) - Flexion at the elbow when the biceps tendon is strike

Supinator jerk: strike the lower end of the radius about 5 cm above the wrist

• Segmental innervation C 5-6• Contraction of brachioradialis and flexion of

the elbow• The biceps often contracts as well slight

flexion of the fingers may occur.

Triceps jerk (C6,7) - Extension at the elbow when the triceps tendon is strike

Knee jerk reflex (L3,L4) - Extension at the knee when the patellar tendon is strike.

Ankle reflex (S1,2) - Plantar flexion at the foot a when Achilles tendon is strike

TESTING MOVEMENT AND POWER

Muscle power.• 0. No muscles contraction visible. • 1. Flicker of contraction but no movement. • 2. Joint movement when effect of gravity eliminated. • 3. Movement against gravity but not against

examiner's resistance.• 4. Movement against resistance but weaker than

normal. • 5. Normal power.

General examination principles • Power– Use power scale– Test two movements at each joint (agonist and

antagonist)– Always compare left with right at each level– Work from proximal to distal

• Paralysis : refers to weakness or loss of voluntary movement.

• 1)Monoplegia: a paralysis of one extremity only • 2)Paraplegia:a symmetric paralysis of both

extremities • 3)Quadriplegia : a paralysis of all 4 extremities • 4)Hemiplegia: a paralysis of one side of the body

limited by the median line• 5)Crossed paralysis: a paralysis of one or more

ipsilateral cranial nerves and contralateral hemiplegia.

• Based on the location, paralysis may be classified as:

• 1)Neurogenic paralysis: caused by lesion of motor neurons or peripheral nerves

• 2)Myogenic paralysis: caused by muscular diseases

• The ultimate goal of strength testing is to decide whether there is true "neurogenic" weakness.

• To determine which muscles/movements are affected.

• Probably the most important decision is whether the weakness is due to damage to upper or lower motor neurons (UMN or LMN)

• UMN weakness is due to damage to the descending motor tracts (especially corticospinal)

• Anywhere in its course from the cerebral cortex through the brain stem and spinal cord.

• UMN weakness is typically associated with increased reflexes and a spastic type of increased tone.

• LMN weakness is due to damage of the anterior horn cells or their axons (found in the peripheral nerves and nerve roots).

• This results in decreased stretch reflexes in the affected muscles and decreased muscle tone.

• Additionally, atrophy usually becomes prominent after the first week or two.

The Neurological ExaminationMotor Examination

Upper Motor Neuron Lower Motor Neuron

Strength

Tone Spasticity

Hypotonia

DTR’s Brisk DTR’s Diminished or Absent DTR’s

Plantar Responses Upgoing Toes Downgoing Toes

Atrophy/Fasiculations None +/-

Co-ordination:

Examination to detect complex movements smoothly and efficiently.

• a. Rebound phenomenon • b. Finger-nose test• c. Heel-shin test• d. Rapid alternating movements

Apraxia: It is difficulty or inability to perform a motor action despite the patient understanding the task.

• Rebound test: Ask the patient to flex at the elbow and resist you as you try to extend the arm.

• Place your other hand on the patients shoulder and turn the patient’s head toward the other direction, to shield the patient’s face and eyes.

• Let the arm go suddenly.• Arm returns to steadying position—normal. • Arm oscillates several time then stays—

abnormal rebound.

• Rapid alternating movements : Demonstrate to the patient (finger tapping, hand tapping, etc.), first in slow motion, and then faster.

• If the patient is able to do the task with normal rate and rhythm—normal.

• If movements are irregular, disorganized, dysrhythmic, uncoordinated—dysdiadochokinesia

• Heel-to-shin test : Done in the supine position.

• Ask the patient to lift one leg up and place the heel on the shin of the other leg, and then smoothly rub it along the shin down toward the toes.

• The test is abnormal if movement is irregular or the heel falls off the leg.

• Finger-nose test :• Ask the patient to touch your finger with his or her

index finger, then to the tip of the nose. • You may move your target finger in different

directions.

• Do one arm at a time.• 1. Patient accurately performs the task: normal. • 2. Patient develops tremor when approaching the

target (your finger or his nose)—intention tremor: cerebellar disease.

• 3. Patient misses the target: past-pointing or dysmetria

The Sensory System

Neural Pathways

• Sensory impulses travel to the brain via– Two ascending neural pathways

1. Spinothalamic tract2. Posterior columns

• Impulses originate in the afferent fibers of the peripheral nerves, are carried through the posterior dorsal root into the spinal cord.

Lateral Spinothalamic Tract

Pain

Temperature

Crude & Light Touch

Posterior Columns

Position

Vibration

Fine touch

Assessment

• Scatter stimuli over the distal and proximal parts of all extremities and trunk to cover most of the dermatomes.

• Abnormal symptoms may indicate need to test the entire body surface– Pain– Numbness– Tingling

• Compare sensations on symmetric parts of the body

• If decrease in sensation– Systematic testing– From point of decreased sensation toward

sensitive area– Note where sensation changes

• Dermatones– C3- front of neck– T4 - nipples– T10 – umbilicus– C6 – thumb– L1 inguinal

• L4 – Knee• L5 – Anterior ankle & footDermatone = skin innervated by the sensory root

of a single spinal nerve

Dermatomes

• Important ones you should remember:

• T4 – level of nipples• T10 – level of umbilicus

• S1 – sole of foot

• Also know upper and lower limb

Light Touch Sensation• Use wisp of cotton• Ask clients to close both eyes and tell you what

they feel and where• Examine the spinal segments sequentially (e.g. in

the upper limb start on the outer border of the arm (C5), then proceed downwards to the lateral border of the forearm and thumb (C6), index finger (C7).

• Normal Findings Correctly identifies light touch

Abnormal findings

– Peripheral neuropathies due to:• Diabetes• Folic acid deficiencies• Alcoholism

– Lesions of the ascending spinal cord, brain stem, cranial nerves, and cerebral cortex

Abnormal findings to Touch

• Anesthesia = absent• Hypoesthesia = decreased• Hyperesthesia = increased

Pain Sensation

• Establishing a baseline for sharpness (e.g. sternal area) before examining the limb.

• Test pin prick sensation down each limb and over the trunk.

• Ask the patient to report if the quality of sensation changes. Either becoming blunter (hyperesthesia).

• Test each dermatome in turn, but also bear in mind peripheral nerve distribution.

• Map out the boundaries of any abnormal area.

Abnormalities to pain

• Analgesia = absence of pain sensation• Hypoalgesia = decreased • Hyperalgesia = increased

Temperature

• Only tested when pain sensation is abnormal. – Temp. & pain travel in the lateral spinothalamic

tract• Test tubes, hot & cold H2O

Vibration

• Low pitched tuning fork (128Hz)• Distal interphalangeal joint (finger & big toe)• Ask what the patient feels.• Ask to tell when the vibration stops and then

touch the fork to stop it. • If impaired- proceed to more proximal joints

or bony prominances.

Posterior Column Tract

• Vibration – often first sense to be lost in peripheral neuropathy.

• Loss = posterior column disease, lesion of peripheral nerve or root

Position ( Kinesthesia)

• Passive movement of extremity• Finger or big toe up and down• Hold by sides b/t thumb and index finger• If position sense is impaired, move proximally

to next joint

Tactile Discrimination

• Sensory cortex• Eyes closed during testing• Stereognosis= identification of an object by

feel– Astereognosis, inability to recognize objects

• Number identification= Graphesthesia– Used when stereognosis prevented due to motor

impairment for ex. In arthritis– Use blunt end of pen/pencil to draw number

• Two-point discrimination– Alternate double with single stimulus– Minimal distance1 from 2 points= less than 5mm

on finger pads

Charting

• If normal– Identifies light touch, dull and sharp sensations to

trunk and extremities.– Vibratory sensation, stereognosis, graphesthesia,

two-point discrimination intact.

• Abnormal results in these tests indicate lesions of the sensory cortex.

• These tests not done on children 6 yrs and younger.

• 65yrs &older – loss of sensation of vibration at the ankle– Position sense in big toe may be lost– Tactile sensation impaired

INFANTS

• Little sensory testing• Hypoesthesia• Responds to pain by crying• General reflex withdrawal of all limbs

Thank you

The motor system consists of • 1. Upper motor neurons • 2. Lower motor neurons • 3. Extra pyramidal motor system • 4. Cerebellar system