5910563 reflex testing

8/6/2019 5910563 Reflex Testing

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Neurologic examinationREFLEX TESTING


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Reflex testing incorporates an assessment of the function and interplayof both sensory and motor pathways. It is simple yet informativeand can give important insights into the integrity of the nervoussystem at many different levels.

Assessment of reflexes is based on a clear understanding of thefollowing principles and relationships:

Tendons connect muscles to bones, usually crossing a joint.When the muscle contracts, the tendon pulls on the bone,causing the attached structure to move.

When the tendon is struck by the reflex hammer, stretch receptorscontained within it generate an impulse that is carried via sensorynerves to the spinal cord. At this juncture, the message istransmitted across a synapse to an appropriate lower motorneuron. An upper motor neuron, whose cell body resides in thebrain, also provides input to this synapse.

The signal then travels down the LMN to the target muscle.

REFLEX TESTING


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The sensory and motor signals that comprise a reflex arc travelover anatomically well characterized pathways. Pathologicprocesses affecting discrete roots or named peripheral nerves willcause the reflex to be diminished or absent. The Achilles Reflexis dependent on the S1 and S2 nerve roots. Herniated discmaterial can put pressure on the S1 nerve root, causing painalong its entire distribution (i.e. the lateral aspect of the lower leg).

If enough pressure if placed on the nerve, it may no longerfunction, causing a loss of the Achilles reflex.

In extreme cases, the patient may develop weakness or evencomplete loss of function of the muscles innervated by the nerveroot, a medical emergency mandating surgical decompression.

A normal response generates an easily observed shortening of

the muscle. This, in turn, causes the attached structure to move.

REFLEX TESTING


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Grade Description

0 Absent; No evidence of contraction

1+ Decreased, but still present (hypo-reflexic)

2+ Normal or physiologic

3+ Increased and maybe normal or pathologic

4+ Markedy hyperactive with transient clonus5+ Markedy hyperactive with sustained clonus

(Repetitive shortening of the muscle after a singlestimulation)

The vigor of contraction is graded on thefollowing scale:


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Technique: You will need to use a reflex hammer when performing

this aspect of the exam. Regardless of the hammer type,proper technique is critical.

The larger hammers have weighted heads, such that ifyou raise them approximately 10 cm from the target andthen release, they will swing into the tendon withadequate force.

The smaller hammers should be swung loosely between

thumb and forefinger.

The Reflex Hammer


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Small Hammers


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Large Hammers


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Technique: The muscle group to be tested must be in a neutral position (i.e.

neither stretched nor contracted). The tendon attached to the muscle(s) which is/are to be tested

must be clearly identified. The extremity should be positionedsuch that the tendon can be easily struck with the reflex hammer.

If you are having trouble locating the tendon, ask the patient tocontract the muscle to which it is attached. When the muscleshortens, you should be able to both see and feel the cord liketendon, confirming its precise location. You may, for example,have some difficulty identifying the Biceps tendon within theAntecubital Fossa. Ask the patient to flex their forearm (i.e.contract their Biceps muscle) while you simultaneously palpatethe fossa. The Biceps tendon should become taut and thus

readily apparent. Strike the tendon with a single, brisk stroke. While this is donefirmly, it should not elicit pain. Occasionally, due to other medicalproblems (e.g. severe arthritis), you will not be able to position thepatients arm in such a way that you are able to strike the tendon.If this occurs, do not cause the patient discomfort. Simply moveon to another aspect of the exam.

REFLEX TESTING


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Technique: This is most easily done with the patient seated, feet dangling

over the edge of the exam table. Other positions: supine, crossingone leg over the other in a figure 4 or a frog-type position.

Identify the Achilles tendon, a taut, discrete, cord-like structure

running from the heel to the muscles of the calf. If you are unsure,ask the patient to plantar flex (i.e. step on the gas).

Strike the tendon directly with your reflex hammer.

Be sure that the calf if exposed so that you can see the musclecontract.

NORMAL RESPONSE: plantar flexion (contraction of theGastrocnemius).

ACHILLES REFLEX (S1, S2 Sciatic Nerve):


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ACHILLES TENDON


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Technique:

This is most easily done with the patient seated, feet danglingover the edge the exam table.

Identify the patellar tendon, a thick, broad band of tissueextending down from the lower aspect of the patella (knee cap). Ifyou are not certain where its located, ask the patient to extendtheir knee. This causes the quadriceps (thigh muscles) to contract

and makes the attached tendon more apparent. Strike the tendon directly with your reflex hammer. If you are

having trouble identifying the exact location of the tendon (e.g. ifthere is a lot of subcutaneous fat), place your index finger firmlyon top of it. Strike your finger, which should then transmit theimpulse.

For the supine patient, support the back of their thigh with yourhands such that the knee is flexed and the quadriceps musclesrelaxed.

NORMAL RESPONSE: The lower leg will extend at the knee.(contraction of the Quadriceps)

PATELLAR REFLEX (L3, L4 Femoral Nerve):


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Patellar Tendon


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PATELLAR REFLEX TESTING


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Technique: Identify the location of the biceps tendon in the antecubital fossa.The tendon will look and feel like a thick cord.

The patients arm can be positioned in one of two ways:

A. Allow the arm to rest in the patients lap, forming an angle ofslightly more then 90 degrees at the elbow.

B. Support the arm in yours, such that your thumb is restingdirectly over the biceps tendon (hold the right arm with your right) It may be difficult to direct your hammer strike such that the force

is transmitted directly on to the biceps tendon, and not dissipatedamongst the rest of the soft tissue in the area. If you aresupporting the patients arm, place your thumb on the tendon and

strike this digit. If the arm is unsupported, place your index ormiddle fingers firmly against the tendon and strike them with thehammer.

NORMAL RESPONSE: elbow flexion

BICEP REFLEX (C5, C6 Musculocutaneous Nerve):


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BICEP TENDON


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BICEP REFLEX TESTING


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BICEP REFLEX TESTING


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Technique: This is most easily done with the patient seated. The lower arm

should be resting loosely on the patients lap. The tendon of the Brachioradialis muscle cannot be seen or well

palpated, which makes this reflex a bit tricky to elicit. The tendoncrosses the radius (thumb side of the lower arm) approximately10 cm proximal to the wrist.

Strike this area with your reflex hammer. Usually, hittinganywhere in the right vicinity will generate the reflex.

NORMAL RESPONSE: elbow flexion and supination of theforearm (turn palm upward).

BRACHIORADIALIS REFLEX (C5, C6 Radial Nerve):


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BRACHIORADIALIS REFLEX


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BRACHIORADIALIS REFLEX


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Technique: Identify the triceps tendon, a discrete, broad structure that can be

palpated as it extends across the elbow to the body of the muscle,located on the back of the upper arm. Ask the patient to extendtheir lower arm at the elbow while you observe and palpate in theappropriate region

The arm can be placed in either of 2 positions:

A. Gently pull the arm out from the patients body, such that itroughly forms a right angle at the shoulder. The lower arm shoulddangle directly downward at the elbow.

B. Have the patient place their hands on their hips. NORMAL RESPONSE: the lower arm to extend at the elbow and

swing away from the body. If the patients hands are on their hips,the arm will not move but the muscle should shorten vigorously .

TRICEP REFLEX (C7, C8 Radial Nerve):


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TRICEP BRACHII TENDON


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DEEP TENDON REFLEXES

Pectoralis Reflex C5 T1

have patient elevate arm; place fingers of your left hand upon the ptsshoulders with your thumb extended downwards. Strike your thumb

directed slightly upwerd toward the pts axilla. NORMAL RESPONSE: muscle contraction can be seen or felt

Pronator Reflex C6 C7 grasp pts hand and hold it vertically so the wrist is suspended from the medial side, strike the distal end of the radius directlywith

horizontal blow NORMAL RESPONSE: pronation of the forearm

Upper Abdominal Muscle Reflex T8 T9 tap the muscles directly near their insertions on the costal margins and

xiphoid processMid Abdominal Muscle Reflex T9 T10

tapping an overlaid finger

Lower Abdominal Muscle Reflex T11 T12 tap the muscle insertion directly near the symphysis pubis


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DEEP TENDON REFLEXES

Adductor Reflex L2 L4 patient supine, arrange the lower limb in slight abduction. Tap directly onthe Adductor magnus, just proximal to its insertion on the medial

epicondyle of the femur NORMAL RESPONSE: the thigh adducts

Hamstring Reflex L4 S2

Patient supine with hips and knees flexed at 90 degrees, and thighrotated slightly outward. place your left hand under the popliteal fossa to compress the medial

hamstring NORMAL RESPONSE: flexion of the knee and contraction of the medial

mass of hamstring


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Normal reflexes require that every aspect of the system functionnormally. 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 theresulting reflex to be diminished or completely absent. Diabetesinduced peripheral neuropathy, for example, is a relatively

common reason for loss of reflexes. Abnormal LMN function will result in decreased or absent

reflexes. If, for example, a peripheral motor neuron is transectedas a result of trauma, the reflex dependent on this nerve will beabsent.

If the UMN is completely transected, as might occur in traumatic

spinal cord injury, the arc receiving input from this nerve becomesdisinhibited, resulting in hyperactive reflexes. Of note,immediately following such an injury, the reflexes are actuallydiminished, with hyper-reflexia developing several weeks later. Asimilar pattern is seen with the death of the cell body of the UMN(located in the brain), as occurs with a stroke affecting the motorcortex of the brain.

Making Clinical Sense of Reflexes:


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Primary disease of the neuro-muscular junction or the muscleitself will result in a loss of reflexes, as disease at the target organ

(i.e. the muscle) precludes movement. A number of systemic disease states can affect reflexes. Some

have their impact through direct toxicity to a specific limb of thesystem. Poorly controlled diabetes, as described above, canresult in a peripheral sensory neuropathy. Extremes of thyroiddisorder can also affect reflexes, though the precise mechanisms

through which this occurs are not clear. Hyperthyroidisim isassociated with hyperreflexia, and hypothyroidism withhyporeflexia.

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 reflexescould be due to impaired sensory input or abnormal motor nervefunction. Only by considering all of the findings, together with theirrate of progression, pattern of distribution (bilateral v unilateral,etc.) and other medical conditions can the clinician makeeducated diagnostic inferences about the results generatedduring reflex testing.

Making Clinical Sense of Reflexes:


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If you are unable to elicit a reflex, stop and consider thefollowing:

Are you striking in the correct place? Confirm the location ofthe tendon by observing and palpating the appropriate regionwhile asking the patient to perform an activity that causes themuscle to shorten, making the attached tendon moreapparent.

Make sure that your hammer strike is falling directly on the

appropriate tendon. If there is a lot of surrounding soft tissuethat could dampen the force of the strike, place a finger firmlyon the correct tendon and use that as your target.

Make sure that the muscle is uncovered so that you can seeany contraction (occasionally the force of the reflex will not besufficient to cause the limb to move).

Sometimes the patient is unable to relax, which can inhibit thereflex even when all is neurologically intact. If this occursduring your assessment of lower extremity reflexes, ask thepatient to interlock their hands and direct them to pull, whileyou simultaneously strike the tendon. This sometimesprovides enough distraction so that the reflex arc is no longerinhibited.

Trouble Shooting


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Occasionally, it will not be possible to elicit reflexes, even

when no neurological disease exists. This is mostcommonly due to a patient's inability to relax. In these

settings, the absence of reflexes are of no clinical

consequence. This assumes that you were otherwise

thorough in your history taking, used appropriateexamination techniques, and otherwise identified no

evidence of disease.

Trouble Shooting


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BRAINSTEM REFLEXES

Direct Pupillary Reaction to Light - the iris constricts when bright light

is shone upon the retina Consensual Pupillary Reaction to Light - stimulation of one retina

causes contralateral constriction of the pupil Ciliospinal Reflex -pinching the skin of the back of neck causes

pupillary dilatation

Corneal Reflex - touching the cornea causes blinking of the eyelids Orbicularis Oculi Reflex - the eyelids close when the retina is

exposed to bright light Auditocephalogyric Reflex - the head and eyes turn toward the

source of a loud sound Jaw Reflex - when the mouth is partially opened and the muscles

relaxed, tapping the chin causes the jaw to close.

The reflex center is in the midpons Gag Reflex - gagging occurs when the parhynx is stroked.

The reflex center is is the medulla


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SUPERFICIAL REFLEXES

have reflex arcs whose receptor organs are in the skinrather than in muscle fibers

adequate stimulus is stroking, scratching or touching these reflexes are lost in disease of the pyramidal tract


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SUPERFICIAL REFLEXES

Upper Abdominal Skin Reflex T5 T8with patient supine, stroke the skin with blunt handle towards the midline watch for ipsilateral contraction of muscles or umbilical deviation towards

the stimulated side

Mid Abdominal Skin Reflex T9 T11

Lower Abdominal Skin Reflex T11 T12Cremasteric Reflex L1 L2

stroke the inner aspect of the thigh from the pubis distad prompt elevation of the testis on the ipsilateral side

Plantar Reflex L4 S2

stroke the sole near its lateral aspect from the heel towards toes produces plantar flexion of the toes

Superficial Anal Reflex L1 L2 stroke the skin of the perianal region the external and anal sphincter contracts


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Glabellar Reflex (Corticopontine)- lightly tapping the forehead between the eyebrows with the fingers

Abnormal response: persistent blepharospasm and closing of theeyes

Snout Reflex (Corticopontine)- tapping the nose

Abnormal response: excessive grimace of the face

Sucking Reflex (Frontal cortex)- stroking the lip with the finger or a tongue depressor

- present in infants but disappears after weaning; reappears in diffuse

lesions of the frontal lobe and commonly noted in dementias

Abnormal response: lips pout and make sucking movements

Chewing Reflex (Frontotemporal cortex)- placing a tongue depressor in the mouth

- seen in dementia, general paresis and anoxic encepalopathy

Abnormal response: chewing movement of the teeth and jaw


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ABNORMAL REFLEXES IN PYRAMIDAL TRACT DISEASE

Babinski Sign (Hallucal Dorsiflexion Reflex) The Babinski response is a test used to assess upper motor

neuron dysfunction and is performed as follows: The patient may either sit or lie supine. Start at the lateral aspect of the foot, near the heel. Apply steady

pressure with the end of the hammer as you move up towards the

ball (area of the metatarsal heads) of the foot. When you reach the ball of the foot, move medially, stroking

across this area. Then test the other foot. Some patients find this test to be particularly noxious

/uncomfortable. Tell them what you are going to do and why. If its

unlikely to contribute important information (e.g. screening examof the normal patient) and they are quite averse, simply skip it.


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Babinski Response Present


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Babinski Sign (Hallucal Dorsiflexion Reflex) Interpretation: In the normal patient, the first movement of the great

toe should be downwards (i.e. plantar flexion). If there is an uppermotor neuron injury (e.g. spinal cord injury, stroke), then the greattoe will dorsiflex and the remainder of the other toes will fan out. Afew additional things to remember:

Newborns normally have a positive Babinksi. It usually goes awayafter about 6 months.

Sometimes you will be unable to generate any response, even in theabsence of disease. Responses must therefore be interpreted in thecontext of the rest of the exam.

If the great toe flexes and the other toes flair, the BabinskiResponse is said to be present. If not (i.e. normal), it is recorded asabsent. For reasons of semantics, the Babinski is not recorded as+ or -.

Withdrawal of the entire foot (due to unpleasant stimulation), is notinterpreted as a positive response


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ABNORMAL REFLEXES IN PYRAMIDAL TRACT DISEASE

Grasp ReflexStroke the pts palm so he grasps your index finger. If present, hecannot release the fingers; lesions of the premotor cortex

Hoffmanns SignHave pt present pronated hand with fingers extended and relaxed.

With your thumb, press his fingernails to flex the terminal digit and

stretch his flexorAbnormal response: flexion and adduction of thumb

Mayers ReflexHave pt present his supinated hand with thumb relaxed and

abducted. Grasp his ring finger and firmly flex the metacarpophalengeal

joint

Normal response: adduction and apposition of the thumb

Palm-Chin Reflex (Radovicis sign)Vigorous scratching or pricking of the thenar eminence causes

ipsilateral contraction of the muscles of the chin


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SIGNS OF MENINGEAL IRRITATION

Nuchal Rigidity- pt cannot place the chin upon the chest

- passive flexion of the neck is limited by involuntary muscle spasm

Spinal Rigidity- movements of the spine are limited by spasms of the Erector spinae

Kernigs Sign- with pt supine, passively flex the hip to 90 deg while the knee is

flexed at about 90 deg

- attempts to extend the knee produce pain iun the hamstring and

resistance

Brudzinskis Sign- with pt supine and the limbs extended, passively flex the neck- produces involuntary flexion of the hips


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Making Sense of Neurological Findings

While compiling information generated from the motor and sensory

examinations, the clinician tries to identify patterns of dysfunctionthat will allow him/her to determine the location of the lesion(s).What follows is one way of making clinical sense of neurologicalfindings.

Is there evidence of motor dysfunction (e.g. weakness, spasticity,tremor)?

If so, does the pattern follow an upper motor neuron or lower motorneuron pattern? If its consistent with a UMN process (e.g. weakness with spasticity),

does this appear to occur at the level of the spinal cord or the brain?Complete cord lesions will affect both sides of the body. Brain levelproblems tend to affect one side or the other. It is, of course, possiblefor a lesion to affect only part of the cord, leading to findings that

lateralize to one side (see below, under description of Brown Sequardlesion).

Is it consistent with an LMN process (e.g. weakness with flaccidity)?Does the weakness follow a specific distribution (e.g. following a spinalnerve root or peripheral nerve distribution)? Bilateral? Distal?


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Making Sense of Neurological Findings

Do the findings on reflex examination support a UMN or LMNprocess (e.g. hyper-reflexic in UMN disorders; hyporeflexic in LMNdisorders)?

Do the findings on Babinski testing (assuming the symptoms involvethe lower extremities) support the presence of a UMN lesion?

Is there impaired sensation? Some disorders, for example, affectonly the Upper or Lower motor pathways, sparing sensation.

Which aspects of sensation are impaired? Are all of the ascendingpathways (e.g. spinothalamic and dorsal columns) affected equally,as might occur with diffuse/systemic disease?

Does the loss in sensation follow a pattern suggestive of dysfunctionat a specific anatomic level? For example, is it at the level of aSpinal nerve root? Or more distally, as would occur with a peripheralnerve problem?

Does the distribution of the sensory deficit correlate with thecorrect motor deficit, assuming one is present? Radial nervecompression, for example, would lead to characteristic motor andsensory findings.


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THE END

5910563 reflex testing

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