reflex

1. DEMONSTRATION
OBJECT –
ELICITATION OF SUPERFICIAL
REFLEXES
REFLEXES
By- Nikita Jain
(Tutor) Physiology

2. Reflex –
It is an rapid, predictable, unconscious and
involuntary response (i.e. contraction of a
muscle or secretion of glands) to a specific
stimulus.

3. Diagram showing the pathway of reflex arc with its different components
Stimulus
1-Receptor
In skin
stimulated
2- sensory
neuron
3- integration
center
interneuron
4 –Motor
neuron
5–Effector

4. APPARATUS –
Patellar Hammer, Examination couch, torch, cotton etc.

5. Parts of knee hammer
1- It consist of a long metallic handle
 At one end on which a triangular shaped soft rubber
piece is attached.
 This rubber piece is used to give a sharp blow to muscle
tendon, in order to get sudden stretching of its muscle.
 On other end of handle is also provided with brush of
nylon hairs and a pointer for testing sensory components
of neurological examination.

6. 2- The rubber piece has two end –
-The broader end
-Pointed or narrow end.
 The broader end is used when the muscle belly is
broader and thin (like tendon of triceps muscle),
 while the pointed end is used when the tendon is
stout and narrow (as of biceps muscle tendon)

7.  The specific nerve roots that comprise the arcs are listed for each
of the major reflexes described below.
CLINICALLY TESTED REFLEXES-
A- Superficial reflexes B- Deep reflexes
1-Planter reflex,
2-Abdominal reflex
1-Conjunctival reflex
2-Corneal reflex
3- Pupillary reflex
1-Knee Jerk
(Or Patellar)
Or Qudericeps
Femoris Jerk
2-Ankle Jerk
(Or
Gasterocnemuis
Jerk)-
3- Triceps Jerk 4- Biceps Jerk
5-Brachioradialis jerk
6-Jaw Jerk

8. Pre- requisites-
1- make sure that the subject is warm and comfortable
2- explain the procedure to the subject before eliciting
the reflex in order to make him relax, reassure and
decrease anxiety and apprehension associated with the
test.
3- subject attention should be diverted from the test to
obtain better response to the stimulus applied.

9. A- Superficial reflexes-
If a stimulus is applied on superficial structures of the body
like skin or mucous membrane, it results in contraction of
underlying muscles. This group of reflexes is polysynaptic.
Following are superficial reflexes -
Reflexes based on cranial nerves-
1-Conjunctival reflex
2-Corneal reflex
3-Ciliospinal reflex
4-Pupillary reflex
Reflexes based on spinal nerves
1-Planter reflex, 2-Abdominal reflex,
Cremestric, Bulbocavernosus, Anal, Scapular reflex

10. CORNEAL REFLEX
• Take a wisp of cotton
and ask the subject to
look to one side and
bring the wisp just to
touch the cornea.
• Obsevation- Closure of
the lids.
• Afferent nerve- Vth
• Efferent nerve- VIIth

11. CONJUCTIVAL REFLEX
• Touch the conjuctiva
with a cotton wool
swab.
• Observation- Closure of
the lids.
• Afferent nerve- Vth
• Efferent nerve- VIIth

12. CILIOSPINAL REFLEX
• Pinch the skin of
neck.
• Observation-
Dilatation of pupil.

13. 1- PLANTER REFLEX- to elicit it the sole should be warm and clean, with leg
completely relaxed.
Procedure –gently scratch the outer edge of the foot with a blunt object (say
key or blunt end of knee hammer handle ) from heel towards the little toe
and then medially along the base of the other toes up to 2nd toe.
Babinski Response Present

15. Interpretation:
In the normal patient, the first movement of the great toe
should be downwards (i.e. plantar flexion). If there is an upper
motor neuron injury (e.g. spinal cord injury, stroke), then the
great toe will dorsiflex and the remainder of the other toes will
fan out.
Normal Response:
Plantar Flexion Of The Foot And Toes.
Babinski sign negative
Abnormal Response:
Babinski sign positive-
Dorsiflexion Of Great Toe and
Fanning Of Other Toes and
Dorsiflexion Of Ankle

16. Level of Spinal cord invovles:
L5, S1,S2 afferent and efferent nerve is tibial nerve
Importance-
The plantar reflex (the Babinski response first described by
Babinski in1896) is important in identifying a UMN lesion;
Examples –
 normally in infants below 1-2 years and deep sleep
 Pathologically in Upper motor neuron lesion, spinal cord
tumour, coma due to any cause etc.

17. 2- ABDOMINAL REFLEX-
Segmental Innervation : T7-12
PROCEDURE- To elicit the abdominal reflex, patient lies relaxed and
supine, with the abdomen uncovered. A key or the reverse end of the
tendon hammer is dragged quickly and lightly across the abdominal skin
lightly in a medial direction across the upper and lower quadrants of the
abdomen parallel to coastal margin and inguinal ligament.
Fig:- abdominal reflex

19. NORMAL RESPONSE - A ripple of contraction of the
underlying abdominal musculature follows the stimulus.
Abdominal reflexes are difficult to elicit in obese or multiparous
women and in anxious patients.
Abnormal Response: are absent in UMN lesions above their
spinal level, as well as in lesions of the local segmental thoracic
root or the spinal cord.

20. Thank you

21. DEEP (OR TENDON) REFLEXES-
 A tendon reflex is the involuntary contraction of a muscle in
response to stretch.
 It is mediated by a reflex arc consisting of an afferent
(sensory) and an efferent (motor) neuron with one synapse
between: that is, a monosynaptic reflex.
 Muscle stretch activates the muscle spindles, which send a
burst of afferent signals that in turn lead to direct efferent
impulses, causing muscle contraction.
 These stretch reflex arcs are served by a particular spinal cord
segment which is modified by the influence of descending
upper motor neurons.

22. Following deep reflexes will be examined in the clinical lab-
1- KNEE JERK (OR PATELLAR) OR QUDERICEPS FEMORIS JERK
Procedure-
In supine position – the examiner's hand is passed under
the knee to be tested and placed on the opposite knee or
the test knee rests on the dorsum of the examiners wrist.
Strike the patellar tendon midway between its origin and
insertion.
In sitting position- Alternately, it can be also more easily
elicited with the subjects sitting up , the leg hanging freely
or crossed legs on the edge of bed.

23. Fig: sitting position
Fig: supine position
Response- A brief contraction of
the quadriceps femoris muscle
results in extension of the knee.
Afferent and efferent paths are
femoral nerve, level of spinal
cord involves –L 2,3,4
Clinical significance- pendullar
in acute cerebellar disease and
present on the side of lesion. In
hypothyroid they are week
while in hyper the jerks are
brisk.

26. 2- ANKLE JERK (or gasterocnemuis jerk)-
PROCEDURE-
In supine position- subject lies in supine, with semiflexed knee and externally
rotated hip. Then with one hand the examiner slightly dorsiflexed the foot so
as to stretch the Achilles tendon and with other hand , tendon is struck on its
posterior surface.
In sitting position- Another method is to ask the subject to kneel over chair so
that the he faces the back of the chair and his ankles lie, over its edge.
RESPONSE- planter flexion of the foot due to contraction of
the calf muscle.
Afferent and efferent nerve – tibal nerve and centre is sacral
1,2 segments.

28. 3- TRICEPS JERK-
PROCEDURE-
In standing/sitting-the arm is flexed to right angle and is
supported on the examiner’s arm. the triceps tendon is then
struck just proximal to the point of the elbow with broader end of
patellar hammer.
In supine position-flex the elbow and allow it to rest across the
subject’ chest. Tap the tendon with hammer.
RESPONSE-
Contraction of triceps muscle with extension at elbow.
Afferent and effernt path- radial nerve; centre is C-6,7

30. 4- BICEPS JERK –
PROCEDURE-
In standing position- The subject’s arm is flexed to a right angle and
the fore arm semipronated and supported on the examiner’s hand.
-The examiner then places hi thumb on the biceps tendon and
strikes it with the narrow end of hammer.
In supine position- The subject’s arm is flexed to a right angle and
the fore arm semipronated, rest over the chest of the subject.
-The examiner then places hi thumb on the biceps tendon and
strikes it with the narrow end of hammer.

31. Biceps Reflex Testing, arm supported Biceps Reflex Testing, in supine
position

32. RESPONSE-
Contraction of biceps muscle with flexion at elbow and slightly
pronation of the fore arm in standing position .
If the patient is in supine position then biceps muscle
contraction is observed.
Afferent and efferent path- musculocutaneous nerve; centre is
C-5,6.

33. 5-SUPINATOR JERK OR BRANCIORADIALIS JERK
Procedure – same as the biceps procedure for supine
position.tap the brachioradialis tendon upon styloid process
of radius.
The tendon of the Brachioradialis muscle cannot be seen or
well palpated, which makes this reflex a bit tricky to elicit. The
tendon crosses the radius (thumb side of the lower arm)
approximately 10 cm proximal to the wrist.
Response - Contraction of brachioradialis muscle with
supination of elbow.
Afferent and efferent path- radial nerve; centre is C-5,6.

35. 6-JAW JERK –
Procedure – Ask the subject to open mouth but not too widely.
Place one finger firmly on chin and tap suddenly with the other
hand ( like percussion).
Response-contraction of massater muscle resulting in closing of
jaw. Sometime this jerk cannot elicit in the healthy subjects.

36. Note-
 if unable to elicit any type of reflex
then apply reinforcement; Jenderassik’s
manoeuvre.
In this subject is asked to perform
some muscular effort, such as clenching
the teeth or locking the fingers of the
hands as hard as possible and then trying
to pull them apart while the examiner
strikes the tendon foe example patellar
tendon.
It results in increasing excitability of the
anterior horn cells for impulses and also
increases of gamma motor neuron
activity which increase the sensitivity of
the spindle cells to strech.

37. Clinical Sense of Reflexes:
Normal reflexes require that every aspect of the system
function normally. Breakdowns cause specific patterns of
dysfunction. These are interpreted as follows:
•Disorders in the sensory limb will prevent or delay the
transmission of the impulse to the spinal cord. This causes the
resulting reflex to be diminished or completely absent. Diabetes
induced peripheral neuropathy (the most common sensory
neuropathy seen in developed countries), for example, is a
relatively common reason for loss of reflexes.
Abnormal lower motor neuron (LMN) function will result in
decreased or absent reflexes. If, for example, a peripheral motor
neuron is transected as a result of trauma, the reflex dependent
on this nerve will be absent

38. If the upper motor neuron (UMN)is completely transected, as
might occur in traumatic spinal cord injury, the arc receiving
input from this nerve becomes disinhibited, resulting in
hyperactive reflexes.
Note, immediately following such an injury, the reflexes are
actually diminished, with hyper-reflexia developing several
weeks later.
A similar pattern is seen with the death of the cell body of the
UMN (located in the brain), as occurs with a stroke affecting the
motor cortex of the brain.
Primary disease of the neuro-muscular junction or the muscle
itself will result in a loss of reflexes, as disease at the target organ
(i.e. the muscle) precludes movement.

39. •A number of systemic disease states can affect reflexes.
•Some have their impact through direct toxicity to a specific limb of the system.
•Poorly controlled diabetes, as described above, can result in a peripheral sensory
neuropathy.
•Extremes of thyroid disorder can also affect reflexes, though the precise
mechanisms through which this occurs are not clear. Hyperthyroidisim is
associated with hyperreflexia, and hypothyroidism with hyporeflexia.
•Detection of abnormal reflexes (either increased or decreased) does not
necessarily tell you which limb of the system is broken, nor what might be causing
the dysfunction.
•Decreased reflexes could be due to impaired sensory input or abnormal motor
nerve function.
•Only by considering all of the findings, together with their rate of progression,
pattern of distribution (bilateral v unilateral, etc.) and other medical conditions can
the clinician make educated diagnostic inferences about the results generated
during reflex testing.

40. Note- the tendon reflex are diminised or absent, on both or one sides, in
lesion involving the affernt pathways (e.g tabes doralis), the anterior horn
cells(poliomyelitis), or the efferent pathways , and also in spinal shock.
Tendon reflex exaggerated in following conditions-
-UML above the anterior horn cells
-Anxiety
--hyperexcitibility of nervous system, as in hyperthyroidism and tetanus
Observation and result-
Tabulated your result as under:
REFLEXES RIGHT SIDE LEFT SIDE REMARK/
GRADING