Interactive Guide to Physical Examination
The motor exam includes evaluation of muscle bulk, tone and strength. It also includes the assessment of body position, coordination and the presence of involuntary movements. You may choose to evaluate each component in a specific region of the body (e.g. examine all motor functions in the arms, then legs, and then trunk) or alternatively evaluate them sequentially (e.g. evaluate strength in all body regions, then evaluate tone, etc.).
Inspect muscles at rest for bulk and symmetry. Pay particular attention for the presence of atrophy. Note involuntary movements such as tremors, tics and fasciculations. Other involuntary movements include choreiform movements, athetoid movements or hemiballismus. If present note amplitude, rate, quality and rhythm as well as any relation to posture and activity.
Muscle tone is assessed by feeling the muscle's resistance to passive stretch. There is a considerable degree of normal variation. To test this, flex and extend the patient's elbow, wrists, knee, and ankle joints. If decreased resistance is suspected, hold the forearm and shake the hand back and forth loosely. The hand should move back and forth freely but should not be overly floppy.
If increased resistance is encountered, try and have the patient relax more, and then determine if the resistance varies as the limb moves or if it is throughout the range of motion and present in both flexion and extension.
Muscle strength is graded according to the Medical Research Council (MRC) scale with zero being no contraction and five representing normal strength.
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Click on the video icon to view a demonstration of the neuromuscular exam. |
Normal coordination requires that the motor, cerebellar, vestibular, and sensory system function in an integrated manner. A patient demonstrating a problem with coordination may have a deficit in any one, or several, of these areas. Coordination is evaluated by observing the patient's gait and station, as well as evaluating rapid alternating movements and point-to-point movements.
The normal gait is effortless, with arms swinging easily at the sides. Turns are smooth. Look for disturbances of posture, balance, loss of arm movement, or abnormal leg movements. A gait that is unstable is termed ataxic. To bring out subtle ataxia, ask the patient to walk heel-to-toe (tandem walking).
The patient should be able to maintain an upright posture, with eyes closed, and feet together, with only minimal swaying. Inability to do this may indicate muscle weakness, loss of proprioception, cerebellar or vestibular difficulties.
The patient should be able to turn one hand, prone to supine, back and forth on his thigh. He should be able to do this rapidly and smoothly, without dysdiadochokinesia. A similar test is to have the patient rapidly tap the index finger against the distal joint of the thumb.
Using his index finger, the patient should be able to alternately touch your index finger, then his nose, back and forth. His movements should be accurate, without tremor or dysmetria.
In testing lower extremities, ask the patient to place one heel on the opposite knee, and slide the heel down the shin to the dorsum of the foot. Some suggest this be done in a supine position to eliminate the benefit of gravity. Normally, these movements are smooth and accurate. When abnormal, the heel may overshoot the knee, and move erratically down the shin.
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Click on the video icon to view a demonstration of the neurologic coordination exam. |
