Uchida Y, Sugioka Y
Department of Orthopedic Surgery, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Electromyogr Clin Neurophysiol. 1993 Sep;33(6):369-73.
In the electrodiagnosis of cubital tunnel syndrome, the abductor digiti minimi (ADM) muscle is frequently used to evoke compound muscle action potentials (CMAP) in order to measure the motor nerve conduction velocity (MNCV) in the ulnar nerve. Slowing of the MNCV across the elbow is a major criteria in the electrodiagnosis of cubital tunnel syndrome. However, in advanced cases, slowing of the MNCV is also seen in the forearm segment, thus, localization of the nerve palsy is sometimes difficult. We evoked CMAP from the flexor carpi ulnaris (FCU) muscle to assess the value of electrophysiological examination of this muscle in the diagnosis of cubital tunnel syndrome. CMAP from the FCU muscle could be evoked in many cases when CMAP from the ADM muscle could not. Also, the motor terminal latency (MTL) of the FCU was prolonged in proportion to the slowing of the MNCV across the elbow. Therefore, electrophysiological examination of the FCU muscle is useful in the diagnosis of cubital tunnel syndrome, especially when intrinsic muscle atrophy is severe and the CMAP from these muscles cannot be evoked.
在肘管综合征的电诊断中，小指展肌（ADM）常被用于引出复合肌肉动作电位（CMAP），以测量尺神经的运动神经传导速度（MNCV）。肘管处MNCV减慢是肘管综合征电诊断的主要标准。然而，在病情严重的病例中，前臂段的MNCV也会减慢，因此，有时难以确定神经麻痹的部位。我们通过尺侧腕屈肌（FCU）引出CMAP，以评估该肌肉的电生理检查在肘管综合征诊断中的价值。当无法从小指展肌引出CMAP时，在许多情况下可从尺侧腕屈肌引出CMAP。此外，尺侧腕屈肌的运动终末潜伏期（MTL）随肘管处MNCV减慢而延长。因此，尺侧腕屈肌的电生理检查对肘管综合征的诊断有用，尤其是在固有肌萎缩严重且无法从这些肌肉引出CMAP时。
