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Clinical Tip

•

The manner in which muscle strength is tested depends

on the patient's ability to follow commands, arollsal,

cooperacion, and activity tolerance, as well as on constraints on the patient, such as positioning, sedation, and medical equipment.

•

If it is nOt possible to grade strength in any of the

described ways, then only the presence, frequency, and

location of spontaneous movements are noted instead.

Muscle Tone

Muscle tOne has been described in a multitude of ways; however, neither

a precise definition nor a quantitative measure has been determined.16 It

is beyond the scope of this chapter to discuss the various definitions of

rone, including variants such as clonus and tremor. For simplicity, muscle

tone is discussed in terms of hyper- or hypotonicity. Hypertollicity, an

increase in muscle contractility, includes spasticity (velocity-dependent

increase in resistance to passive stretch) and rigidity (increased agonist

and antagonist muscle tension) secondary ro a neurologic lesion of the

CNS or upper motor neuron system. 17 Hypotollicity, a decrease in muscle contractility, includes flaccidity (diminished resistance to passive stretching and tendon reflexes)17 from a neurologic lesion of the lower

mOtor neuron system (or as in the early Stage of spinal cord injury [SCrl).

Regardless of the specific definition of muscle tone, clinicians agree that

muscle tone may change according to a variety of facrors, including

stress, febrile state, pain, body position, medical status, medication, eNS

arousal, and degree of volitional movement. IS

Muscle tone can be evaluated in the following ways:

• Passively as mild (i.e., mild resistance to movement with quick

stretch), moderate (i.e., moderate resistance to movement, even

without quick stretch), or severe ( i.e., resistance great enough to

prevent movement of a joint) 19

•

Passively or actively as the ability or inability to achieve full

joint range of motion

•

Actively as the ability to complete functional mobility and volitional movement

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•

As abnormal decorticate (flexion) or decerebrate (extension)

posturing. (Decortication is the result of a hemispheric or internal

capsule lesion that results in a disruption of the corticospinal

tract.14 Decerebration is the result of a brain stem lesion and is

thus considered a sign of deteriorating neurologic st3ms.14 A

patient may demonstrate one or both of these postures.)

Reflexes

A reflex is a motor response to a sensory stimulus and is used to

assess the integrity of the motor system in the conscious or unconscious patient. The reflexes most commonly tested are deep tendon reflexes ( DTRs). A DTR should elicit a muscle contraction of the

tendon stimulated. Table 4- 14 describes DTRs according to spinal

level and expected response. DTR testing should proceed in the

following manner:

1.

The patient should be sining or supine and as relaxed as possible.

2. The joint to be tested should be in mid position to stretch

the tendon.

3. The tendon is then directly tapped with a reflex hammer.

Both sides should be compared. Reflexes are typically graded as

present (normal, exaggerated, or depressed) or absent. Reflexes can

also be graded on a scale of 0-4, as described in Table 4-15.

Depressed reflexes signify lower motOr neuron disease or neuropathy.

Exaggerated reflexes signify upper motor neuron disease, or they may

be due to hyperthyroidism, electtOlyte imbalance, or other metabolic

abnormalities.2o

Table 4-14. Deep Tendon Reflexes of the Upper and Lower Extremities

Reflex

Spinal Level

Normal Response

Biceps

CS

Elbow flexion

Brachioradialis

C6

Elbow flexion

Triceps

C7

Elbow extension

Patellar

L4

Knee extension

Posterior tibialis

L5

Planrar flexion and inversion

Achilles

S l

Plantar flexion

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Table 4-15. Deep Tendon Reflex Grades and Interpretacion

Grade

Response

Inrerpretation

0

No response

Abnormal

1 +

Diminished or sluggish response

Low normal

2+

Active response

Normal

3+

Brisk response

High normal

4+

Very brisk response, with or with-

Abnormal

our clonus

Source: Data from LS Bickley, RA Hockelman. Bate's Guide to Physical Examination

and History Taking (7th cd). Philadelphia: Lippincott, 1999.

Clinical Tip

The numeric results of DTR resting may appear in a stick

figure drawing in the medical record. The DTR grades are

placed next to each of the main DTR sites. An arrow may

appear next to the stick figure as well. Arrows pointing

upward signify hyper-reflexia; conversely, arrows pointing

downward signify hyporeflexia.

A superficial reflex should elicit a muscle contraction from the

cornea, mucous membrane, or area of the skin that is stimulated.

The most frequently tested superficial reflexes are the corneal

(which involve CNs V and VII), gag and swallowing (which

involve CNs IX and X), and perianal (which involves 53-55).

These reflexes arc evaluated by physicians and are graded as

present or absent. Superficial reflexes may be abnormal cutaneous

responses or recurrent primitive reflexes that are graded as present

or absent. The mOSt commonly tested cutaneous reflex is the Babillski sigll. A positive (abnormal) Babinski sign is great-tOe extension with splaying of the toes in response to stroking the lateral planrar surface of rhe foot wirh the opposite end of a reflex hammer. It indicates corticospinal rract damage.

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Sensation

Sensation testing evaluates the abiliry ro sense lighr and deep rouch,

proprioception, temperature, vibration sense, and superficial and deep

pain. For each modality, the neck, trunk, and extremities are tested bilaterally, proceeding in a dermaromal pattern. For more reliable sensation resring results, rhe parient should look away from rhe area being tesred.