The following #reflexes are routinely tested, and the response elicited is graded from zero to 5+ with 2+ being normal. For each deep tendon reflex, the right and left side should be compared with particular attention paid to asymmetry—that is reflexes that are brisker on one side than on the other. The examiner should use several senses. The reflex response of a limb can be seen, but it can also be felt by the examiner's hand that supports the limb. It can also be heard in the form of a dull thud as the reflex hammer hits an areflexic limb. Asymmetry of only one reflex is often a reflection of hyperreflexia on the side of a nerve or spinal root injury. In contrast, if all or most of the deep tendon reflex are brisker on one side, the patient may be displaying hyperreflexia resulting from damage to the pyramidal system.



The biceps reflex can be tested when the patient's elbow is flexed at a right angle and the examiner places a thumb on the patient's bicep tendon and then strikes the thumb. Normally, a slight contraction of the bicep muscle occurs. The triceps reflex will be tested with the patient's elbow supported in the examiner's hand. The triceps tendon is sharply percussed just above the olecranon. Contraction of the triceps muscle with extension of the arm usually results. The patellar reflex testing occurs when the patellar tendon is tapped with the percussion hammer. The patient is usually seated on the edge of a table or bed with the legs hanging loose. For patients who are bedridden, the knees can be flexed over the supporting arm of the examiner with the heels resting lightly on the bed. The Achilles reflex is best elicited by having the patient kneel on a chair with ankles and feet projecting over the edge of the chair. The Achilles tendon is then struck with the percussion hammer.



Additional reflexes are tested in special situations such as coma, spinal cord injury, frontal lobe dysfunction, and neurodegenerative disorders. These would include the abdominal reflex, tested when the patient is lying supine with relaxed abdominal muscles. Stroke the skin of each quadrant of the abdomen briskly with a pin from the periphery toward the umbilicus, and, normally, local abdominal muscles contract causing the umbilicus to move toward the quadrant stimulated. The plantar response can be tested by stroking the outer surface of the sole of the foot lightly with a large pin or wooden applicator from the heel toward the base of the little toe and then across the ball of the foot. The normal plantar response consists of plantar flexion of all toes with slight inversion and flexion of the distal portion of the foot. In abnormal responses, there may be extensions of the great toe with fanning and flexion of the other toes, called the Babinski reflex. The Babinski reflex suggests dysfunction of the corticospinal system, although it does not in itself tell the examiner the rostrocaudal location of the lesion.



Clonus may be elicited in a patient with exaggerated reflexes. Wrist clonus is sometimes elicited by forcible flexion or extension of the wrists. Patellar clonus can be elicited by a sudden downward movement of the patella with a consequent clonic contraction of the quadriceps. Angle clonus is tested by quickly flexing the foot dorsally, producing clonic contractions of the calf muscles. Clonus can be sustained or transient and is usually measured in a number of beats; three to four beats of clonus can be elicited at ankles in some normal individuals.