Examination of motor systemPresentation Transcript
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.
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 Typesi. Physiological tremor :- hyperthyroidism, alcoholism.ii. Coarse tremor (slow) :-Parkinsons 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 REFLEXESReflexes1.SUPERFICIAL REFLEXES2. DEEP TENDON REFLEXES SUPERFICIAL REFLEXES - elicited by striking skin or mucous membrane.
CREMASTERIC REFLEX(L1-2) :• Abduct and externally rotate the patients 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. Hoffmans 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 patients proximal phalanges. - Observe the flexion of the patients finger
Biceps jerk (C5-C6) - Flexion at theelbow 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 atthe 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 POWERMuscle 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 examiners 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 Examination Motor Examination Upper Motor Neuron Lower Motor NeuronStrengthTone Spasticity HypotoniaDTR’s Brisk DTR’s Diminished or Absent DTR’sPlantar Responses Upgoing Toes Downgoing ToesAtrophy/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 tract 2. 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
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
The motor system consists of• 1. Upper motor neurons• 2. Lower motor neurons• 3. Extra pyramidal motor system• 4. Cerebellar system