Brown W F
J Neurol Neurosurg Psychiatry. 1972 Dec;35(6):845-52. doi: 10.1136/jnnp.35.6.845.
A method for estimating the number of motor units in median innervated thenar muscles is described. In normal human subjects under 40 years of age, the mean and 1 SD was 253+34. The number of motor units falls with increasing age, especially after mid life, so that elderly subjects often have less than one-half the number in youth despite good strength. The cause is not known but probably includes peripheral nerve trauma and `primary neuronal cell death'.
本文描述了一种估计正中神经支配的鱼际肌运动单位数量的方法。在40岁以下的正常人类受试者中，平均值和1个标准差为253±34。运动单位的数量随年龄增长而下降，尤其是中年以后，因此尽管老年人力量良好，但他们的运动单位数量往往不到年轻人的一半。原因尚不清楚，但可能包括周围神经损伤和“原发性神经元细胞死亡”。
