Functional, anatomical, and neurophysiological study of human upper limb muscles

1.肘关节屈肌的功能和解剖学研究。通过电激活两个肘关节屈肌（肱二头肌：BB，肱桡肌：BR）产生前臂旋后，在健康受试者中进行了检查。这些肌肉分别通过带有计算机控制的多通道刺激器的导线电极进行电刺激。激活BB诱导屈曲和旋后，激活BR诱导屈曲。在保持前臂俯卧的情况下，用足够的刺激强度激活肘部。在这种情况下，BB的额外激活伴随着BR刺激强度的降低导致旋后而不屈曲。由于肱三头肌在整个运动过程中没有收缩，这支持了一种理论，即屈肌活动的代偿性变化允许BB在没有屈曲的情况下进行旋后运动。肘关节肌肉的神经生理学研究。采用自主激活运动单元刺激后时间直方图的方法研究了人类肱二头肌（BB）、肱桡肌（BR）和旋前圆肌（PT）之间的神经投射。对BB、BR和PT神经的电条件刺激分别抑制了BR和PT、BB和PT以及BB的运动单位。这种抑制是在远低于运动阈值的刺激强度下产生的。抑制的潜伏期比同音促进的潜伏期长0 ~ 2ms。这些发现表明，BB和BR之间、BB和PT之间以及BR到PR之间存在抑制投射，并且这种抑制是通过I组传入和寡核苷酸（二或三）突触连锁介导的。

1.Functional and anatomical studies of the elbow flexors.Forearm supination produced by electrical activation of two elbow flexors (biceps brachii : BB,brachioradialis : BR) was examined in healthy human subjests. The muscles were activated separately by electrical stimulation through wire electrodes with a computer-controlled multi-channel stimulator. Activation of BB induced flexion and supination and that of BR induced flexion. Activation of BR with adequate stimulation intensity provided holding of elbow with maintaining the forearm prone. In this situation, additional activation of BB accompanied with a decrease of stimulation intensity for BR resulted in supination without flexion. Since the triceps brachii showed no contraction throughout the motion, it supports a theory that compensatory changes of activities among the flexors permit BB to work for supination without flexion.2.Neurophysiological studies of the muscles crossing the elbow joint.Neural projections among the biceps brachii (BB), brachioradialis (BR), and pronator teres (PT) in humans were studied using the method of post-stimulus time histograms of voluntarily activated motor units. Electrical conditioning stimuli to the BB,BR and PT nerves resulted in inhibition in motor units of BR and PT,of BB and PT,and of BB,respectively. The inhibition was induced with the stimulation intensity well below the motor threshold. The latency of the inhibition was 0-2ms longer than that of the homonymous facilitation. These findings suggest that inhibitiory projections between BB and BR,and between BB and PT,and from BR to PR exist and the inhibition is mediated through group I afferents and oligo (di or tri) -synaptic linkage.