Overview of the Motor Examination



Overview of the Motor Examination





Examination of motor functions includes the determination of muscle power, evaluation of muscle tone and bulk, and observation for abnormal movements. Examination of coordination and gait are closely related to the motor examination. Coordination is often viewed as a cerebellar function, but integrity of the entire motor system is essential for normal coordination and control of fine motor movements. Station (standing) and gait (walking) are complex, and involve much more than motor function; they are usually assessed separately from the motor examination.

Both the peripheral and central nervous systems participate in motor activity, and various functional components have to be evaluated individually. The lowest echelon of motor activity is the motor unit, which consists of an alpha motor neuron in the spinal cord or brainstem, its axon, and all of the muscle fibers it innervates. The segmental or spinal cord level mediates simple segmental reflexes, such as the withdrawal reflex, and includes the activity of many motor units and elements of both excitation and inhibition involving agonists, synergists, and antagonists. Various descending suprasegmental motor systems modulate the activity that occurs at the segmental level. The pyramidal (corticospinal) system arises from the primary motor cortex in the precentral gyrus. The corticospinal system is the primary, overarching suprasegmental motor control mechanism. The function of the corticospinal system is modulated and adjusted by the activity of the extrapyramidal and cerebellar systems. The extrapyramidal system arises primarily in the basal ganglia. Centers in the brainstem that give rise to the vestibulospinal, rubrospinal, and related pathways are of importance in postural mechanisms and standing and righting reflexes. The psychomotor, or cortical associative, level of motor control has to do with memory, initiative, and conscious and unconscious control of motor activity that arises primarily from the motor association cortex anterior to the motor strip.



OVERVIEW OF CLINICAL MANIFESTATIONS OF DISEASE OF THE MOTOR SYSTEM

The most common manifestation of motor system disease is weakness. Other abnormalities include alterations in muscle tone, changes in muscle size and shape, abnormal involuntary movements, and defective coordination.

Jun 19, 2016 | Posted by in NEUROLOGY | Comments Off on Overview of the Motor Examination

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