Muscular function is controlled by the brain. Assessment of muscular function is a routine part of the standard neurological examination. Most neurological testing turns out to involve a stimulus to which a muscular response is observed. This includes shining a light in the eyes and seeing the pupils constrict (a muscular response), tapping under the kneecap with a reflex hammer and seeing the foot kick out, and the majority of other neurological testing responses.

These muscular responses (technically, motor nerve responses) can be used to understand the effects of other sensory stimuli in addition to those used in the conventional neurological examination. Any stimulus can be used as a challenge to the system, while observing for changes in motor responses of muscles as a reflection of the effect of the stimulus.

By observing these changes in the way the nervous system controls and coordinates muscle function, Dr. Yanuck can assess the impact on the neurological function from a broad range of stimuli. This aids in the assessment of problems with the body’s chemistry, immune or hormonal imbalances, stress and other aspects of physiology. So the muscular system is a window through which additional useful information about the functions of the body can be derived.