1. Examination of the
Sensory System
In association with
Dr David Smith
Consultant Neurologist
Walton Centre for Neurology
and Neurosurgery
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2. The sensory system 1
 Sensory information, detected at peripheral
receptors, travels via peripheral nerves,
nerve roots, spinal cord, brainstem and
thalamus to sensory cortex
 Pain and Temperature sensation
 carried by small unmyelinated fibres
 Vibration and Proprioception (joint
position)
 carried by large myelinated fibres
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3. The sensory system 2
 Pain and Temperature sensation
 carried in the spinothalamic tract
 decussates (crosses over) immediately in the
spinal cord
 Vibration and Proprioception (joint
position)
 are carried in the dorsal columns
 Ascend on the same side of spinal cord
 cross over in the brain stem
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Spinal cord section
 Posterior column
ipsilateral (crosses at
medulla)
 proprioception
 vibration
 Spinothalamic tract
contralateral (crosses at
spinal level)
 pain
 light touch
 temperature
• Motor supply
 Anterior corticospinal
 Lateral corticospinal

5. Normal sensory examination
 Normal sensation allows a patient to detect
 pain (pinprick) and temperature
 in whichever area is tested,
 vibration
 at tips of fingers and toes
 joint position (i.e. small amplitude movements )
 at distal joints
 In order to identify abnormality, it is important to
know what normal means
 In someone with no sensory symptoms, it is not
essential to examine the sensory system
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6. sensory pathway
Peripheral receptor
peripheral nerves
nerve roots
spinal cord
thalamus
sensory cortex
 Localisation of problems can be determined by knowledge of area of
skin supplied by peripheral nerves, sensory dermatomes, decussation of
spinothalamic tract and dorsal columns
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Dermatomes of the upper limb
C7
C3
C4
C5
C6
C8
T1
T2
C5
C6

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Dermatomes of the lower limb
S4
S5L1
L2
L3
L4
L5
S1
S2
S3
A dermatome is an
area of skin supplied
by a single spinal
nerve for the
modalities of
sensation.A
knowledge of the
dermatomes can
help to localise
problems involving
the spinal cord or
nerves

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Dermatomes of the trunk
C2
C3
C4
T2
T5
T10
V1
V2
V3

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Testing light touch
 Use a wisp of Cotton wool
or a fine paint brush
 Ask the patient to respond
when stimulus is detected
 Dab the skin and then
withdraw the stimulus -
do not drag the cotton
wool across the skin
 Compare one side with the
other

11. Pain (superficial)
 Use a disposable neurotip, pin or
unfolded paper clip
 Do NOT use a hypodermic needle
 Always dispose of “sharp” safely
 Explain and show the touching
with “sharp” and “blunt” on an
unaffected area
 Test by randomly using sharp and
blunt (negative stimulus) noting
patient‟s response in each
dermatome (always try to apply
same pressure)
 Start distally and move proximally
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12. In Clinical Practice
 Allow the patient to describe the distribution of
altered sensation
 Demonstrate the nature of test sensation in an area
of skin the patient perceives to be normal
 Test sensation within the area reported to be
abnormal
 Map the extent of altered sensation
 Decide if this area makes anatomical sense (relates
to or associated with a spinal, dermatomal or
peripheral /cutaneous nerve pattern of altered
sensation.
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13. Testing Proprioception1
 Hold distal interphalangeal joint
of patient‟s great toe/thumb or
finger between thumb and
index finger of your left hand
 Make a small amplitude
movement of the joint using
your right hand to demonstrate
„up‟ and „down‟
 Repeat with patient‟s eyes
closed
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14. Proprioception 2
 If patient cannot detect small
amplitude movements, or
makes errors, increase the
amplitude of movement
 If patient cannot detect larger
amplitude movements, test
proprioception at a more
proximal joint (see next slide)
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15. Proprioception - order of testing
Upper limb
 distal interphalangeal
joint
 proximal
interphalangeal joint,
 metocarpophalangeal
joint
 Wrist
 Elbow
 shoulder
Lower limb –
 interphalangeal joint of
the hallux,
 metatarsophalangeal
joint,
 ankle
 knee
 hip
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Proprioceptive sense tends to decline with age

16. Testing proprioception 3
(also see coordination)
 ask patient to close eyes and stretch
arms, then to touch tip of their nose with
their index finger.
 If proprioception is normal this will be done
accurately
 With patient standing, feet approx.20cm
apart, and eyes closed, gently push them
on chest.
 If proprioception is intact balance is
maintained.
 This is a negative Romberg's test
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17. Testing vibration sense 1
 With a 128 Hz tuning fork create vibration by either
taping it gently against your hand or by pushing the
prongs towards one another
 To avoid reducing the vibration hold at the round
thumb rest just under the fork, the flat rest at the
base is held against the patient.
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Demonstrate on a boney prominence away from the affected area
(forehead or sternum for example)

18. Testing vibration sense 2
 Place base of 128 Hz tuning
fork on tip of a finger or toe
 Ask patient „Can you feel
that buzzing?‟
 If they can not, move
proximally, testing vibration
sense at bony prominences
(hallux, medial malleolus …
clavicle) until the vibration is
detected
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19. Patterns of sensory loss
 As with motor examination, the pattern of sensory
loss helps to localise a lesion to specific parts of the
nervous system
 The initial distinction is whether the lesion is in the
central or peripheral nervous system
 A good way of achieving this is to recognise
patterns of sensory loss caused by
 spinal cord lesions (central)
 peripheral neuropathy (peripheral)
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20. Spinal Cord Lesion
 Sensation is lost or altered below the level of
the lesion
 this is called a sensory level
 The extent of the lesion determines whether
the loss of sensation is uni- or bi-lateral
Familiarity with cross-sections of the cord and
sites of where the main tracts decussate
(cross over) will enable you to understand
the detail of the pattern of sensory loss.
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Spinal cord section
 Posterior (dorsal)
column ipsilateral
(crosses at medulla)
 proprioception
 vibration
 Spinothalamic tract
contralateral (crosses at
spinal level)
 pain
 light touch
 temperature
• Motor supply
 Anterior corticospinal
 Lateral corticospinal

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Patterns of sensory loss
Complete transverse lesion of the cord
Right
Loss of proprioception
Loss of vibration
Loss of temperature
Loss of pain
Loss of light touch
Left
Loss of proprioception
Loss of vibration
Loss of temperature
Loss of pain
Loss of light touch

23. Peripheral Neuropathy
 Loss, or altered, sensation starts at the end
of the longest nerves; i.e. in the toes and
spreads proximally
 The fingers are affected after the toes/feet
 This produces a “glove and stocking” pattern
of sensory loss
 The type of nerve fibre affected (myelinated,
unmyelinated or both) determines which
modalities are lost.
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