Reflexes: Exam Demonstration

Upper extremity reflexes (biceps, brachioradialis, triceps)

Reflexes (stretch reflexes or deep tendon reflexes/DTR) depend on the integrity of both the sensory system and the motor system in the spinal cord. The sensory stimulus enters the spinal cord at a specific level, but the motor innervation involves more than one spinal cord level because of the distribution of peripheral nerves in the plexus. The biceps reflex is mediated by spinal cord levels C5 and C6. The brachioradialis reflex is mediated mainly by C6. The triceps reflex is mediated mainly by C7.

The video demonstrates elicitation of normal biceps, brachioradialis, and triceps reflexes.  It is important to compare symmetry of reflexes, since patients may vary in the reaction to stimulation.  Hyperreflexia is associated with upper motor neuron disease.  Hyporeflexia is associated with lower motor neuron disease or with decreased sensation.

Reflexes are graded on a scale of 0 to 4.  A grade of 2 indicates normal reflexes.  A grade of 3 indicates hyperreflexia; 4 indicates hyperreflexia with clonus.  Decreased relexes are indicated by 1 (hyporeflexia) or 0 (no reflex elicited, even using the Jurassic maneuver. 

Clck the play button to watch the video

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