Examination of sensory system

Sensory system. Pathway, Dematomes, Various lesions of sensory system.

1. Dr. ShaluJain
MD Scholor
Pt. KhushilalSharma Govt. Auto. AyurvedaCollege And Institute, Bhopal (M.P.)

2. Five senses

3. Sensory Pathway

5. Sensory Dermatomes

Dermatomes :-it is an area of skin that is mainly supplied
by single spinal nerve.
Purpose :-testing of dermatomes is part of the

Purpose :-testing of dermatomes is part of the
neurological examination looking for rediculopathyas
sensation changes within a specific dermatomes may help
in determining the pahologicaldisc level.

7. 
C1-nocutaneoussupply;suppliesmeninges

C2-occiput,earlobe,angleofjaw

C3-napeofneck

C4-aboveclavicle

C4-aboveclavicle

C5-deltoid;overaspectofshouldertip

C6-radialhalfofforearmincludingthinareminenceand
thumb

C7-longestspinousprocess–longestfinger(middlefinger)

C8-littlefinger,hypothinareminenceandulnaraspectof
hand

8. 
T1-ulnaraspectofforearm

T2-ulnaraspectofarm

T3-liesinaxilla

T4-nipple

T4-nipple

T8,T10,T12–supplyribmargin,umblicusandpubis
respectively

L1-inguinalligament

L3-liesatknee

L4-medialaspectofleg

L5-lateralaspectofleg

9. 
S1 -includes little toe, tendo-achilles, strip of skin above
it and sole

S2 -calf musleand hamstring

S3, S4, S5 –perianalregion

S3, S4, S5 –perianalregion

10. Modalities of sensation to be
tested

Exteroceptivesensations

ProproceptiveSensations

Cortical sensations

11. ExteroceptiveSenstion/Superficial sensation
Receptors in skin & mucus membrane.

Tactile or touch

Pain Sensation

Temperature sensation

12. Touch

fine touch –tested by cotton wool

Crude touch –by blunt object

13. Temperature

Twotesttubesone
containinghotwaterand
theothercrushediceis
takenandplacedonallthetakenandplacedonallthe
partsofthe

14. Pain

Superficial pain:-tested with a
pin prick

Deep pain :-tested by pressing the
calves, tendoachillisor testes

15. Proprioceptivesensation

Position sense

Joint sense/ sense of passive movement

Vibratory sense

16. Vibration
Assessment ofvibration senseis the best clinical test of
the dorsal column pathway.
A low-frequency (128?Hz) tuning fork is applied to bony
prominences.prominences.
The patient (with closed eyes) is asked to report when the
vibration starts and stop.

17. s

18. Joint sense

Fixingthejoint,thefinger/
toeismovedatterminal
interphalangealjoint,interphalangealjoint,
eitherupordownby
holdingthesidesofdigits.

Patienttotellthedirection
i.e.eitherupordown.

19. Position sense
•
Apartoflimb/armis
placedindefiniteposition
andthenheisaskedtoandthenheisaskedto
dentethepositionorplace
theotherlimbinsimilar
position.

20. Cortical sensory functions

Point localisation(tactile location)

Two point Discrimination

Tactile extinction

Sterognosis

Graphesthesia

21. Sense of localzationtest

Touchapartofpatient
bodywithhiseyesclosed

Askhimtoopentheeyes

Askhimtoopentheeyes
andplacehisfingerofthat
part

22. Two point discrimination test

Ability to distinguish the contact of two separate points applied
simultaneously to the skin.

Finger pulp & lips –3-5 mm

Palm –2-3 cm

Palm –2-3 cm

Sole –4 cm

Dorsum of foot -5 cm above

Legs –5cm and above

Back –5cm above

If two point discrimination is lost in the presence of intact
posterior column sensations, it indicates a paritallobe lesion.

23. Cont…

24. Tactile extinction

Whentwostimuliareapplied
simultaneouslytotwo
symmetricalportionofthe
body,thepatientneglectthe
oneontheoppositesideofthe
lesion,.

Thoughindividuallyhe
appriciatesthestimulusonboth
side.

25. Graphesthesia

Theabilitytorecognizea
numberorletterwrittenin
thepalmwithclosedeyes.

Thisabilityislostin
sensorycortexlesion

26. Stereognosistest

The abiltyto identify a
suitable object after
careful palpation.careful palpation.

This ability is lost in
sensory cortex lesion.

27. Sensory Changes
In
Various DiseasesVarious Diseases

28. Poly neuropathy

Symmetricalgloveand
stockinganesthesia
(affectingdistalparts(affectingdistalparts
more)involvingallthe
modalitiesofsensations.

Thereiscalftenderness

29. Caudaequinaand Conuslesions

Lossofallmodalitiesof
sensationsinvolving
especiallylowersacralespeciallylowersacral
segmentsleadingto
perianalanesthesia

30. Multiple roots involvement

Therearevaryingdegreesofimpairementofcutaneous
sensationsinthedistributionofthenerveroots
Painsensationismoreaffectedthantouch.

Painsensationismoreaffectedthantouch.

31. Complete section of spinal cord

Allsensationsareaboished
belowaperticularlevel,witha
narrowzoneofhyperesthesiaat
theuppermarginofthe
anestheticzone

Insomepatientswithhighcord
compressionsacralfibresmay
besparedresultinginsacral
sparing.

32. Hemi section of spinal cord

Painandtemperatureis
lostafewsegmentbelowa
perticularlevelontheperticularlevelonthe
oppositesidewhilst
vibration,position,and
jointsensesareaffectedon
thesameside.

33. Syringomyelia

Lossofpaintemperature
sensation.

Touch,vibration,jointand

Touch,vibration,jointand
positionsensesarenormal.

Thisisalsocalled
dissociateanesthesia.

34. Anterior spinal syndrome

Lossofpain,temperature
andtouchbelowalevel
onbothsideswithonbothsideswith
preservedposition,joint
andvibrationsense.

Eg.Anteriorspinalartery
thrombosis

35. Posterior spinal syndrome

Lossofpoosition,joint
andvibrationsensebelow
alevelwithnormaltouch,alevelwithnormaltouch,
temperatureandpain
senses.

Eg.Tabesdorsalis

36. Brain Stem Syndrome

Lossoftouchpain
temeratureonsameside
ofthefaceandoppositeofthefaceandopposite
sideofthebodydueto
involvementoftrigeminal
tractornucleusor
spinothalamictract.

37. Thalamic syndrome

Lossofallmodalitiesof
sensationsontheopposite
sideofbody

Positionsensearemore

Positionsensearemore
affectedthantheother
sensation.

Theremaybespontaneous
pain&discomfortofthe
mosttorturinganddisabling
type.