1. Examination of the
Motor System
In association with
Dr David Smith
Consultant Neurologist
Walton Centre for Neurology
and Neurosurgery
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Note
 This study guide is designed with
right-handed examiners in mind.
 please substitute appropriately if left-
handed
 Arrows on photographs depict the
direction of movement of the limb

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CONTENTS
 Tone and Clonus
 Limb Power
 Reflexes

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The motor system
Messages travel from the motor cortex via subcortical
nuclei and brainstem to spinal cord, thence to
nerve roots, peripheral nerves and finally to
muscles
 Upper Motor Neurone (UMN)
 From the motor cortex to anterior horn cell of
the spinal cord
 Lower Motor Neurone (LMN)
 from anterior horn cell to neuromuscular
junction

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Testing muscle
tone and
clonus

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Tone
 NORMAL
 passive movement of the limbs should be neither floppy
nor stiff
 INCREASED due to -
 lesions of pyramidal tract (UMN) – SPASTICITY
 or lesions of the extrapyramidal tract – RIGIDITY
 REDUCED
 caused by LMN lesions, is called FLACCIDITY
Abnormal tone will be accompanied by other signs
which help to localise the lesion
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Testing for spasticity in the arms 1
 Support the elbow with your left
hand
 Hold patient’s hand as if shaking
hands
 Rapidly supinate and pronate the
arm
 Use the same technique on each
arm
 Always use the same hand to
assess movement for the patients
right and left

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Testing for spasticity in the arms 2
 While still supporting
the elbow passively
flex and extend the
elbow
 Use same technique
on both arms
 If tone is normal there
will be no resistance to
these movements

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Testing for spasticity in the legs 1
 With the patient relaxed, place your hands on the
thigh and roll the whole leg
 Observe the movement of the foot
 If tone is normal the range of movement of the foot
is similar to the rotation of the leg
Alternatively
 Flex and extend the knee
 If tone is normal there should be no resistance to
this movement

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Lower Limb Tone 2

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Testing for spasticity in the legs 2
(Clonus)
Position the patient with the
knee flexed and the hip
externally rotated
 Sharply dorsiflex the foot
In most people with normal
tone the foot will not move
 But 2-3 beats of clonus
(plantar flexion followed by
dorsiflexion of the foot)
can be within normal limits
Sustained clonus is a
sign of an upper motor
neurone problem

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Pyramidal tract (UMN) lesion;
SPASTICITY
 There is initial resistance to movement which
gives way as the movement continues
 Arm; SUPINATOR CATCH
 Leg; CLASP KNIFE phenomenon
 There is usually SUSTAINED CLONUS
(>3-4 beats)
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Testing Power

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The grading of muscle power (MRC)
Grade Meaning
0 Complete paralysis
1 Flicker of contraction possible
2 Movement possible if gravity eliminated
3 Movement against gravity but not resistance
4 Movement possible against some resistance
5 Power normal (it is not normally possible to
overcome a normal adult’s power)
6

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Patterns of weakness 1
 Help to localise the problem within the
nervous system
 A limited examination allows you to
differentiate between UMN and LMN lesions
 Different patterns of LMN weakness may
require more detailed examination
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Motor power
 Ask the patient to make the required
movement
 Attempt to overcome the movement
remembering that this is not a test of relative
strength
 Avoid mechanical advantage to the examiner
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Summary of motor supply to the upper limb
Extension
C7/8
Flexion
C5/6
Extension
C7/8
Flexion
C6/7
Extension
C7/8
Flexion
C7/8
Abduction
C5/6 Adduction
C6/7/8
Adduction
C8/T1

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Shoulder abduction (C5/6) and adduction
(C6/7/8)
Position patient with shoulders
abducted to 90°
 Ask patient to maintain position
whilst you attempt to overcome by
pressing down on upper arm
Position patient with arms at approx
30° of abduction, with elbows
flexed
 Ask patient to bring elbows
towards side against resistance
“Stop me
pushing your
arms down”
“Stop me
pushing your
arms up”

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Elbow flexion 2
(C5/6) and extension (C7/8)
Position patient with elbow
flexed
 Ask them to resist your attempt
to straighten arm
Position patient with elbow
extended beyond 90 °
 Ask them to resist your attempt
to flex the elbow (‘push me
away’)
“Pull me towards you”
“Push me away”

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Finger extension (C7, C8)
Position patient with
fingers extended
 While supporting wrist
ask them to resist your
attempt to flex fingers
“Stop me trying to
bend your fingers
down”

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Finger flexion
 Ask patient to curl fingers
towards palm
 And to keep fingers flexed
while you attempt to
straighten them
Alternatively
 ask them to squeeze two of
your fingers placed in
either of the patient’s palms
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“Stop me
pulling
your
fingers
straight”
“Squeeze
my fingers”

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Summary of lower limb motor supply
Abduction
L4/5/S1
Adduction
L2/3/4
Inversion
L5/S1
Eversion
L5/S1
Extension
L3/4
Flexion
L2/3Extension
L5/S1/2
Dorsiflexion
L4
Plantar flexion
S1/S2
Flexion
L5/S1

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Hip flexion (L2/3) and extension (L5/S1/2)
Position the patient with the leg
elevated to approx 30°
 Attempt to overcome by
pressing down on thigh
Position patient with leg flat on
couch
 Place your hand underneath
thigh and attempt to elevate
leg while patient presses
down
“Stop me
trying to raise
your leg up”
“Stop me
pushing your
leg down”

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Knee flexion (L5/S1)
Position patient seated with knee flexed
 Place your left hand on patient’s thigh
 Place your right hand behind heel/ankle/calf
 Ask patient to bring heel towards buttocks against
resistance
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“Stop me trying to straighten your leg”

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Knee extension (L3/4)
Position patient seated
with knee flexed
 Place your left hand on
patient’s thigh
 Place your right hand
over patient’s shin
 Ask patient to
straighten leg against
resistance
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“Stop me trying to bend your
knee”

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Dorsiflexion (L4) and plantar flexion (S1/2) of the foot
 Dorsiflexion: Ask patient
to bring foot upwards
 Attempt to overcome by
pressing down on foot
 Plantar flexion: Ask
patient to push foot down
 Attempt to overcome by
pressing upwards on sole
“Stop me pushing your
foot down”
“Stop me pushing your
foot up”

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Patterns of weakness 2
 UMN lesion
 there is weakness of the;
 extensors in the arms
 flexors in the legs
 The unopposed action of unaffected muscles produces the
characteristic posture seen in patients with stroke
 LMN lesion
 involvement of nerve endings (peripheral
neuropathy) produces a predominantly distal
pattern of weakness
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Testing the
reflexes

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Reflexes
Normal reflex arc requires :-
 Stimulus to stretch receptors
 Intact sensory afferent pathway
 Link with a motor unit
 Intact motor neurone
 Contractile element
The order in which you test reflexes should be logical
and may vary from one examiner to another
The patient must be relaxed

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Documenting reflexes
Absent -
Present with reinforcement +/-
Normal + or ++
Brisk +++
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Reflexes can be recorded as follows:

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The reflexes
Biceps (C5/6)
Triceps (C7/8)
Supinator
(C5/6)
Finger (C8)
Ankle (S1/2)
Plantar (L5/S1/2)
Knee (L3/4)
Abdominal

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Testing for reflexes
 Position the limb correctly
 Hold the tendon hammer like a hammer
 Place your finger over the tendon and strike it,
 for some reflexes you will strike the tendon itself (see
slides below)
 (except the ankle – see slide 38)
 Observe the relevant muscle for contraction
 (not the limb movement)
 Be aware of the range of normality.
 Abnormal reflexes rarely seen without other relevant
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Reinforcement
Where a reflex appears difficult
to elicit, reinforcement might
be tried.
 Ask the patient to close their
eyes:
 lower limb
 ask the patient to grasp the
fingers of each hand and to
pull apart on instruction just as
the reflex is tested
 upper limb
 the teeth may be clenched
Reinforcement for a lower limb
reflex – with patient’s eyes
closed

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The upper limb
Reflex Testing

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Supinator (brachioradialis) reflex (C5/6)
 Position patient sitting
relaxed, with elbows
flexed and hands
resting on thigh/groin
 Place your left
index/middle finger(s)
over supinator tendon
 Strike finger(s) with
falling head of hammer
 Observe slight elbow
flexion or contraction of
belly of brachioradialis
 Observe for contraction of
brachioradialis here
 You may notice momentary
elbow flexion

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Biceps reflex (C5/6)
 In same position clasp
patient’s elbow so that
biceps tendon can be felt
under your thumb or finger
 Strike your thumb or finger
 Observe elbow flexion
 there may be little movement
 but you should feel the
contraction

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Triceps reflex (C7/8)
Position patient with their
arm across the
abdomen with elbow
flexed to 90°
 Strike the triceps
tendon direct
 Observe
 for elbow extension
 or contraction of the
muscle bellyYou may feel muscle contract
with free hand

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The finger jerk (C8)
Ask patient to rest their
fingers on index and middle
fingers of your left hand and
curl their fingers slightly
 Strike your fingers
 Patient’s fingers may flex
 This can be normal

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The lower limb
Reflex Testing

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Knee reflex (L3/4)
Support one or both
knees, so they are
slightly bent
 Strike the patellar
tendon direct
 Observe
 quadriceps contraction
 with or without knee
extension
Infrapatellar ligament
Patella

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Ankle reflex S1/2
Patient is seated
Place your left hand on
ball of patient's foot
Passively dorsiflex the
ankle
 Strike your fingers
 Observe/feel for
plantarflexion

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Plantar reflex (L5/S1/2)
Patient seated with leg
flat on couch
 Drag thumbnail or
blunt object along the
lateral border of the
foot and across the
sole towards other side
 The normal response is
flexion of the big toe
 may be absent if feet
are cold

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Patterns of reflex change
 UMN lesion
 Reflexes brisk below the level of the lesion
 plantar response is usually extensor
 A pathologically brisk finger flexion jerk is the
upper limb equivalent of an extensor plantar
response
 LMN lesion (peripheral neuropathy)
 reflexes are absent
 distal reflexes are first to be lost
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Summary
Parameter UMN lesion LMN lesion (peripheral
neuropathy)*
Posture Flexed UL, Extended LL May be wasting,
fasciculation
Tone Increased (spasticity) Reduced (flaccidity)
Power Weakness of UL
extensors and LL flexors
Distal weakness
Reflexes Brisk Absent
Plantar response Extensor Flexor or absent
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There are other patterns of lower motor neurone
lesions (nerve root, individual peripheral nerve).
*

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Reminder
 What you have learned so far will allow you
to distinguish between UMN and LMN
lesions
 In future you will learn additional skills
needed to localise lesions according to
particular presentations
 E.g. examination of the intrinsic hand muscles
in someone with weakness or tingling in the
hand/fingers.
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Finger abduction
Support patient’s wrist with your
left hand
 Ask patient to spread fingers
wide
 Ask patient to maintain this
position while you try to push
little finger inwards
 Ask patient to maintain this
position while you try to push
index finger inwards
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“Stop me pushing your
fingers”

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Thumb abduction (T1, median)
Support patient’s wrist
with your left hand
 Ask patient to lift
thumb upwards
 Ask them to maintain
that position against
resistance
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“Stop me pushing your thumb
down to your palm”
Thumb abduction is 90° to finger abduction

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Thumb opposition (T1,Median)
Support patient’s wrist
with left hand
 Ask patient to place tip
of thumb onto tip of
index finger
 And to hold this
position while you try to
separate the thumb
and index finger
48
“Stop me pulling your fingers
apart”

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Thumb adduction (T1, Ulnar)
Support patient’s wrist
with your left hand
 Ask patient to trap your
index and middle
fingers between the
base of their thumb
and their index finger
 Ask them to maintain
that position while you
try to lift their thumb
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“Stop me trying to lift your
thumb up”