Examination of the Upper Limbs

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The Neurological Examination

General aspects. The examiner should ask the patient which hand he or she mostly uses, right or left. Only persons who use a pair of scissors, a knife, or a sewing needle with their left hand, or write with the left hand, are true left handers. Any abnormalities of muscle bulk should be noted, in particular isolated atrophy of muscle groups. Fasciculations must be deliberately sought: in our experience, these involuntary contractions of groups of muscle fibers, which induce no movement, can be seen under the skin only by careful observation of the unclothed patient from an adequate distance and

for a sufficient length of time. The trophic state of the skin, the papillary pattern of the fingertips, and the configuration of the nails should also be assessed. Important positive findings include anomalies of finger posture, tremor, or other involuntary movements. The mobility of the larger joints should be tested individually and the pulses in the limbs should be felt. Vascular bruits should be listened for in the supraclavicular fossa when indicated.

Fig. 3.20 Finger−nose test. a Normal, smooth, confident movement. b Ataxic movement c Intention tremor: the closer the finger comes to its target (nose), the more it deviates from the ideal line of approach.

Fig. 3.21 Rebound phenomenon due to a cerebellar lesion. a Method of testing: the examiner’s other hand protects the patient’s face. b When the examiner suddenly releases the patient’s actively flexed arm, the ensuing involuntary flexion should be promptly braked. c Braking is inadequate (the rebound phenomenon is positive) in the presence of an ipsilateral cerebellar lesion

b

a

c

a

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The Neurological Examination

Muscle Tone and Strength

Muscle tone in the upper limbs can be tested with wide-amplitude passive movement of the radiocarpal joint or of the elbow. The movement should be rapid, but not rhythmic (so that the patient cannot predict its course). Diminished muscle tone (hypotonia) is a characteristic sign of intrinsic muscle lesions, peripheral nerve lesions, ipsilateral cerebellar dysfunction, and hy-

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perkinetic extrapyramidal diseases. Spasticity is a type of elevated muscle tone produced by lesions of the pyramidal pathway (Fig. 3.22a). The resistance of a spastic upper limb to passive movement is usually strong at first, but may then suddenly give way (“clasp-knife phenomenon”); alternatively, it may increase on continued passive movement. Rigidity is a viscous or waxy resistance to passive movement that can be felt to an equal extent throughout the entire movement; it is

Fig. 3.23 Testing for the cogwheel phenomenon in the radiocarpal joint. The examiner fixes the patient’s forearm with one hand, grasps the patient’s fingers with the other, and moves them slowly (but not rhythmically) back and forth.

Table 3.4 Grading of muscle strength.

The 0−5 scale of the British Medical Research Council (MRC).

M0 = no muscle contraction

M1 = visible contraction not resulting in movement

M2 = movement of the body part only when the effect of gravity is eliminated

M3 = movement against gravity

M4 = movement against moderate resistance

M5 = full strength

(Grades M3 and M4 can be optionally subdivided by adding plus or minus signs)

most commonly found in Parkinson disease (Fig. 3.22b). The accompanying parkinsonian cogwheel phenomenon is best appreciated at the radiocarpal joint. The examiner should fix the patient’s forearm with one hand, grasp the patient’s fingertips with the other, and alternately flex and extend the radiocarpal joint, slowly and with a wide excursion, but not in perfect rhythm (Fig. 3.23). The examiner will then feel multiple, brief impulses of resistance at irregular intervals, giving the overall impression of a saccadic movement (Fig. 3.22c). Elevated muscle tone may also result from active opposition to passive movement when the patient apparently cannot relax the muscular contraction. This phenomenon, known by the German term Gegenhalten (“opposition”), is seen in frontal lobe lesions.

Muscle strength is tested in groups of muscles that carry out a single movement, or, if necessary, in individual muscles. The patient is asked to contract the corresponding muscle(s) actively against the examiner’s resistance. The examiner then judges the strength of contraction at the end-point of the related movement. Thus, the examiner tests biceps strength by trying to extend the patient’s flexed elbow against resistance and triceps strength by trying to flex the extended elbow against resistance. The evaluation of potential lesions of individual nerve roots or peripheral nerves requires specific testing of the particular muscles or muscle

groups innervated by these nerves (see p. 208). For the purpose of documentation, muscle strength can be graded semiquantitatively with the MRC scale shown in Table 3.4. Incomplete paralysis is called paresis and complete paralysis is called plegia. Further terms describe the distribution of weakness in the body: hemiparesis or hemiplegia affects one side of the body, paraparesis or paraplegia affects both lower limbs, and quadriparesis or quadriplegia affects all four limbs (less common synonyms for the last two are tetraparesis and tetraplegia). Paralysis of both arms, or brachial diplegia, is a rare occurrence.

Reflexes

Types of reflexes. Reflexes are processes that are induced by a specific stimulus, always take the same course, and cannot be voluntarily influenced by either the patient or the examiner. For the intrinsic muscle reflexes, alternatively called proprioceptive muscle reflexes, the site (muscle) of the eliciting stimulus is the same as that of the reflex contraction; for extrinsic (exteroceptive) reflexes, the stimulus and the response are at different sites and the afferent and efferent arms of the reflex loop, therefore, belong to different peripheral nerves or segmental nerve roots. Extrinsic reflexes become less intense (habituate) on repeated stimulation.

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The Neurological Examination

Corneal reflex gently touching the cornea from the side, e. g., with a wisp of cotton or piece of tissue paper; the eye looks medially

Bell phenome- attempted active eye closure non (palpebro- while the examiner holds the oculogyric re- upper lids open

flex)

Gluteal reflex stroking the skin over the gluteus maximus m.

Bulbocavernosus gently pinching the glans penis; reflex pinprick on the skin of the dor-

sum of the penis

Anal reflex pinprick on the skin of the perianal region or perineum, patient in lateral decubitus position with flexed hip and knee

proof that ptosis is not due to peripheral paresis or myasthenia

release phenomenon (disinhibition) due to diffuse cortical injury, e. g., postanoxic

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The Neurological Examination

Intrinsic muscle reflexes of the upper limb. The intrinsic muscle reflexes are elicited by a rapid, and adequately forceful, blow on the tendon of a muscle or on the bone to which the tendon is attached. The resulting, transient stretching of the muscle excites receptors in the muscle spindles, in which afferent impulses are generated. These travel to the spinal cord and excite the α-motor neurons innervating the stimulated muscle (usually by way of interneurons at the same segmental level). The upper limb reflexes that are usually tested are the triceps, biceps, and radial periosteal reflexes (Table 3.5). The last-named reflex is elicited by a tap on the styloid process of the radius; this is followed by contraction, not only of the brachioradialis m., but also of

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the biceps and brachialis mm. The elicitation of these reflexes is illustrated in Fig. 3.24.

The two important finger flexor reflexes are essentially variations of the same reflex. The Trömner reflex is elicited by a rapid tap on the pads of the patient’s lightly flexed fingers. The response consists of flexion of the distal interphalangeal joints of the fingers and thumb (only in the hand that was stimulated, not in the other hand). To elicit Hoffmann sign, the examiner gently grasps the distal phalanx of one of the patient’s fingers (usually the middle finger) between his or her own thumb and index finger, then lets it snap back as the thumb slides off the patient’s fingernail. The response is the same as in the Trömner reflex (Fig. 3.25).

Fig. 3.25 Elicitation of the Trömner reflex.

The more common abnormalities of the intrinsic muscle reflexes and their significance are presented in Table 3.8.

Facilitating maneuvers. Initially faint or not clearly elicitable intrinsic muscle reflexes can be enhanced with various maneuvers based on the principle that preloading of the intrafusal muscle spindle fibers makes them more sensitive to stretch. Forceful contraction of practically any muscle group in the body results in a generalized sensitization of all muscle spindle fibers. Thus, all of the intrinsic muscle reflexes can be made stronger by having the patient forcefully lift his or her head from the headrest (in the supine position), clench the teeth, make fists, strongly plantar-flex the feet, or interlock the hands and pull hard (this is called the Jendrassik handgrip). These maneuvers are illustrated in Fig. 3.26.

Pyramidal tract signs in the upper limb. Lesions along the pyramidal pathway produce characteristic changes in the pattern of the reflexes that are normally present, as well as other, pathological reflexes that are normally absent. Evidence for a lesion of the pyramidal pathway is generally less obvious in the upper limb than in the