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A study of motor unit structure by means of scanning EMG
Author(s) -
Gootzen Theis H. J. M.,
Vingerhoets Dick J. M.,
Stegeman Dick F.
Publication year - 1992
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880150314
Subject(s) - motor unit , medicine , anatomy , physical medicine and rehabilitation , electromyography
We used the scanning EMG technique to investigate the structure of human quadriceps muscle motor units. A group of healthy volunteers and 2 groups of patients with proven neurogenic or myogenic neuromuscular pathology have been studied. In total, 86 scans were obtained. An estimate of the motor unit territory ( S ) separates the 2 patient groups: the majority of territories of myogenic patients are smaller than 4 mm, whereas almost all motor unit territories of neurogenic patients are larger. However, the sizes of the pathologic units only occasionally exceed the upper and lower limits of normal units (2 to 8 mm). The myogenic scans show, on average, a much larger temporal dispersion ( T ) between the MUAPs within a motor unit than the normal scans. These findings are in accordance with observations with the same technique by others. For the neuropathic scans, there is a significant positive correlation between S and T , which is completely absent in myopathic scans. These observations are confronted with current morphometrical knowledge on motor unit physiology and anatomy.