Lecture Slides Presented at SIMS by Medical Unit SIMS Hospital

1. Dr Tahir Bashir
Assistant professor
Medical Unit IV

2.  Examining the sensory system provides
information regarding the integrity of the
Spinothalamic Tract, posterior columns
of the spinal cord and parietal lobes of
the brain.

3. Equipment
 Cotton ball
 Objects to feel, quarter or key etc.
 Test tubes with hot/cold H2O
 Tuning fork, low pitched

4. Screening Test
 Only necessary to evaluate the following
Lateral aspect of upper thighs
Inner aspect of upper arms
Dorsal or palmer surface of hands
Bottom or dorsal surface of feet

5. Neural Pathways
 Sensory impulses travel to the brain via
 2 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.

6. Lateral Spinothalmic Tract
 Pain
 Temperature
 Crude & Light Touch

7. Posterior Columns
 Position
 Vibration
 Fine touch

8. 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

9.  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
Map borders of deficient area, Diagram

10.  Note if the pattern of sensory loss is
“distal”
Glove & stocking ( hands & feet)
 Dermatones
C3- front of neck
T4 - nipples
T10 – umbilicus
C6 – thumb
L1 inguinal

11. Dermatomes
 L4 – Knee
 L5 – Anterior ankle & foot
Dermatome = band of skin innervated by
the sensory root of a single spinal nerve.

12. Light Touch Sensation
 Use wisp of cotton
Ask clients to close both eyes and tell you
what they feel and where
 Normal Findings
Correctly identifies light touch
In some older clients light touch and pain
sensations may be decreased

13. Abnormal findings to Touch
 Anesthesia = absent
 Hypoesthesia = decreased
 Hyperesthesia = increased

14. Pain Sensation
 Pin prick
 Tongue blade, dull & sharp
 Ask to distinguish
2 sec. b/t each stimulus to avoid
summation
(frequent consecutive stimuli percieved as
one strong stimulus)

15. Abnormalities to pain
 Analgesia = absence of pain sensation
 Hypalgesia = decreased
 Hyperalgesia = increased
Apply lightest pressure to obtain response

16. Temperature
 Only tested when pain sensation is
abnormal.
Temp. & pain travel in the lateral
spinothalamic tract
 Test tubes, hot & cold H2O

17. 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.

18. 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
If position sense intact distally , then it
is OK proximally.

19. Tactile Discrimination
 Sensory cortex
 Eyes closed during testing
 Stereognosis= identification of an object
by feel
Astereognosis, inability to recognize objects

20.  Number identification= GraphesthesiaNumber 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

21.  Point Localization
Touch pt’s skin
Open eyes and point to where touched
Useful trunk & legs
 Extinction
Simultaneously stimulate same area both
sides of body
Ask how many points felt and where

22. charting
 If normal
Identifies light touch, dull and sharp
sensations to trunk and extremities.
Vibratory sensation, stereognosis,
graphesthesia, two-point discrimination
intact.

23.  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

24. Infants and toddlers
 Little sensory testing
 Hypoesthesia
 Responds to pain by crying
 General reflex withdrawal of all limbs
 7 – 9mos.can localize stimulus

25. Mapping of sensory lesion