by Alberto Esquenazi, MD, Nathaniel H. Mayer, MD.Moss Rehabilitation Research Institute, Albert Einstein Healthcare Network, Philadelphia, PA, USA.
Multiple muscle agonists and antagonists acting for all the joint movements in the upper and lower limb exist. This redundancy of motor control is very valuable in normal physiology, but when a central nervous system injury with resulting upper motor neuron syndrome takes place, the source of the functional impairment may be difficult to localize. In this paper we discuss the use of gait and motor control analysis studies as a tool particularly useful in determining the specific muscles that may be producing limb dysfunction. We present the most frequent patterns of upper motor neuron dysfunction that affect the upper and lower limb as a result of upper motor neuron syndrome. A case description of the features, the electromyographic patterns, and their functional implications are used. Our objective is to clarify the understanding of these patterns of dysfunction and their focal cause with the intent to improved care of the patient with upper motor neuron syndrome.