背景與目的：神經根壓迫會對於運動神經纖維與所支配的肌肉力量造成影響，而肌電圖檢查則常被使用在檢查此類病人可能產生神經根病變的節數。然而肌電圖的診斷是否能反映神經肌肉系統功能的改變卻仍不清楚。本研究主要目的在於探討腰神經根壓迫病人的肌肉力量是否與肌電圖診斷的受損節數有關。方法：16位腰脊髓腔狹窄且伴隨有單側神經根病變的病人接受肌電圖與下肢肌肉力量檢查。肌電圖檢查診斷神經根壓迫的條件為兩條以上受同一神經根支配之肌肉有異常自主電位活動、相同節數之脊柱旁肌肉亦有不正常發現以及感覺神經檢查結果為正常。等長肌肉力量測試則使用手握式肌肉力量測試儀測試兩側髖屈曲肌、膝屈曲肌與伸直肌、踝背曲肌與腳指伸肌的力量。分別比較相同節數肌電圖診斷異常與正常病人間的肌肉力量(受試者之間比較)與不同節數受壓迫病人好壞腳肌肉力量(受試者本身比較)的差異。結果：除所有病人腰椎第五節都受到壓迫所以未作受試者之間比較之外，神經根壓迫並未對腰椎第四節與薦椎第一節肌電圖診斷異常病人肌肉力量造成影響，而病人好壞腳之間的肌肉力量也無顯著差異。結論：腰神經根壓迫病人的下肢肌肉力量不會受到肌電圖診斷異常的影響，而肌電圖診斷無異常也不代表神經肌肉系統受到較低程度的損傷。因此不管肌電圖診斷結果為何，臨床上病人好壞腳肌肉力量都需要經過詳細檢查與評估。（物理治療2003;28(3):109-116）

Background and Purpose: Nerve root compression may affect motor nerve fibers and the strength of the muscles supplied by the compressed nerve root may subsequently be compromised. Electromyography (EMG) examination has been used to assess the level of involvement for patients with suspected radiculopathies. However, whether EMG findings correspond to changes in neuromuscular function is not clear. The purpose of this study was to investigate whether muscle strength was related to the involved nerve root level identified by EMG examination in patients with lumbar nerve root compression. Methods: Sixteen patients with unilateral lumbosacral radiculopathy attributable to spinal stenosis participated in the study, and received needle EMG study and strength test of the lower extremities. The presence of abnormal spontaneous activity in two or more muscles innervated by the same nerve root combined with corroborative paraspinal muscle involvement and normal segmental sensory stimulation in the EMG studies were used as diagnostic criteria of nerve root compression. The isometric strength of the bilateral hip flexion, knee extension and flexion, ankle dorsiflexion, and toes extension was tested with a hand-held dynamometer in standardized position. The strength of the subjects with EMG abnormality at a specific involvement level was compared with subjects who showed normal EMG at the same level, i.e. between-subject comparison. Also the strength of the same subject was compared between the involved and noninvolved sides. Results: Because all the patients were involved at L5, no between-subject comparison was made for this level. Nerve root compression did not have significant effect on the muscle strength for subjects with L4 or S1 EMG abnormalities. The strength between the involved side and noninvolved side (within-subject comparison) also showed nonsignificant differences. Conclusions: The lower extremity muscle strength of the patients with lumbar nerve root compression did not appear to be affected by the presence of EMG abnormalities. Thus, a lack of EMG abnormality did not necessarily indicate a lesser degree of neuromuscular involvement. The strength of the muscles affected and unaffected by nerve root compression should all be carefully assessed regardless of their EMG findings. (FJPT 2003;28(3):109-116)