Bates’ Visual Guide to Physical Examination

17.5 Examining the Motor System Video Transcript

Narrator: As you assess the motor system, focus first on body position and involuntary movements. The necessity important characteristics of the muscles: bulk, tone and especially strength. Also assess coordination.

Observe the patient’s body position during movement and at rest. Watch for involuntary movements such as tremors, tics or fasciculations. Inspect the size and contours of the muscles. Do the muscles look flat or concave suggesting atrophy? If so, is the atrophy unilateral or bilateral? Is it proximal or distal? Atrophy of hand muscles may occur with normal aging. When looking for atrophy, pay special attention to the hands, shoulders, and thighs. In older adults, look especially for wasting of the quadriceps which increases risk of falls. Then evaluate the patient’s muscle tone or resistance to passive stretch.

Encourage the patient to relax. Take one hand in yours, and while supporting the elbow flex and extend the patient’s fingers, wrist, elbow and put the shoulder through a moderate range of motion. On each side note muscle tone, the resistance offered to your movements. Remember, in muscle testing, the patient resists and the examiner overcomes the patient’s resistance. To assess muscle tone in the legs, support the patient’s high with one hand. Grasp the foot with the other and flex and extend the patient’s knee and ankle on each side. Note the patient’s resistance to your movements. Assess both legs in turn.

As you assess muscle strength, keep in mind that a person’s dominant side is usually slightly stronger than the nondominant side.

You will grade your patient’s muscle strength on a scale of 0–5 with 0 indicating no muscular contraction detected and 5 indicating active movement against full resistance without evident fatigue. This is considered a normal response.

Begin by testing flexion of the biceps muscle by having the patient bend his arm at the elbow and pull against your hand and test extension of the triceps by having the patient push against your hand. Next, test flexion of the patient’s wrist and extension of the patient’s wrists.

Next, test the patient’s grip. Across the middle and index fingers to cushion them and ask the patient to squeeze as hard as possible while you try to remove your fingers. Normally, you should have trouble removing them.

Continue testing muscle strength by asking the patient to turn his palm down and spread his fingers. Check abduction by trying to force them together. Test opposition of the thumb by asking the patient to try to touch the tip of his little finger with his thumb while you resist the movement. This may be impaired and carpal tunnel syndrome.

Examination of the motor system of the lower extremities is best performed with the patient lying supine on the examination table. Test flexion at the hip by placing your hand on the patient’s thigh and asking the patient to raise the leg against your hand. Then test hip extension by the gluteus maximus by placing your hand on the patient’s posterior thigh and providing resistance.

To test hip abduction by the gluteus medius and gluteus maximus, place your hands firmly on the table outside the patient’s needs. Ask the patient to spread both legs against your hands. To test the hip abductors place your hands between the patient’s knees and ask the patient to bring the knees together. Note the strength.

Continue by testing muscle strength at the knee by supporting the patient’s knee in flexion and asking the patient to straighten the leg against your hand. The quadriceps is the strongest muscle in the body, so expect a forceful response. To assess knee flexion by the hamstrings, shift your hand position but leave the patient’s leg flexed up in knee. Tell the patient to keep the foot down as you try to straighten the leg.

Finally, test dorsiflexion at the ankle by asking the patient to pull up against your hand, and plantar flexion by asking the patient to push down against your hand.