Jakobsson F, Edström L, Grimby L, Thornell L E
Department of Neurology, Karolinska Hospital, Stockholm, Sweden.
J Neurol Sci. 1991 Sep;105(1):49-56. doi: 10.1016/0022-510x(91)90117-p.
The tibialis anterior (TA) is a muscle activated mainly during walking. Its use during the step cycle was studied in 10 patients (55.8 +/- 8.8 years) with chronic hemiplegia (duration 3-18 years) and related to the muscle fibre composition, size and expression of isoforms of myosin heavy chains (MHCs). In the average step cycle the integrated surface EMG of the paralysed TA did in the majority of the hemiplegic patients not exceed 10% of that recorded during maximal contraction of the normal leg. The type I fibre percentage in the paralysed TA subject was 57.4% as compared with 79.4% in normal muscles (P less than 0.05). The range of axonal conduction velocities in the peroneal nerve did not differ in paralysed and non-paralysed leg, suggesting that there was no selective loss of one class of motoneurons. The type II fibres consisted of IIA (66%) and IIB (31%), in contrast to the normal TA muscle where less than 1% of the muscle fibres are of type IIB. The incidence of fibres in the biopsies with both slow and fast MHCs had a mean value of 3.5% (range 0.7-9%). The type I and type II muscle fibres had normal sizes with cross-sectional area 4511 +/- 962 microns 2 and 6181 +/- 1062 microns 2. No selective type II atrophy was seen. Occasional hypertrophic type I and II fibres were seen in 4 patients.(ABSTRACT TRUNCATED AT 250 WORDS)
胫骨前肌（TA）是主要在行走时被激活的肌肉。对10例（年龄55.8±8.8岁）慢性偏瘫患者（病程3 - 18年）在步行周期中该肌肉的使用情况进行了研究，并将其与肌纤维组成、大小以及肌球蛋白重链（MHCs）亚型的表达相关联。在平均步行周期中，大多数偏瘫患者患侧TA的表面肌电图积分不超过健侧在最大收缩时记录值的10%。患侧TA中I型纤维百分比为57.4%，而正常肌肉中为79.4%（P<0.05）。腓总神经的轴突传导速度范围在患侧和健侧腿并无差异，这表明没有一类运动神经元发生选择性丧失。II型纤维由IIA（66%）和IIB（31%）组成，而正常TA肌肉中IIB型肌纤维少于1%。活检中同时含有慢速和快速MHCs的纤维发生率平均值为3.5%（范围0.7 - 9%）。I型和II型肌纤维大小正常，横截面积分别为4511±962平方微米和6181±1062平方微米。未观察到选择性II型萎缩。4例患者中可见偶尔的I型和II型肥大纤维。（摘要截断于250字）
