DIGIT FLEXOR MUSCLES IN CAT - THEIR ACTION AND MOTOR UNITS
DIGIT FLEXOR MUSCLES IN CAT - THEIR ACTION AND MOTOR UNITS
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DOI：
10.1002/jmor.1051370305
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发表时间：
1972-01-01
影响因子：
1.5
通讯作者：
NEMETH, WC
中科院分区：
文献类型：
--
作者：
GOSLOW, GE;STUART, DG;NEMETH, WC
在猫后肢的主要指屈肌中，探讨了肌肉活动与运动单位力学特性之间的关系：跖屈肌（PL）、趾短屈肌（FDB）、拇长屈肌（FHL）和趾长屈肌（FDL）。对肌肉活动的一般观察表明，PL是踝伸肌和指屈肌。PL和FHL被证明是主要的力量贡献者与FDL发挥较小的，但仍然显着的role. PL，FHL和FDB运动单位的机械性能进行了研究，通过记录抽搐和强直张力产生的电刺激的单个α轴突，功能上孤立的腹根细丝。这些数据与Olson和Swett（1966）报道的趾长屈肌（FDL）的类似数据进行了比较。我们的样本（114 PL，60 FDB和124 FHL单位）显示PL，FDB和FHL具有均匀快速收缩时间的单位（分别为22，27和27毫秒）。PL装置产生的强直张力最大（3至160，平均62 gm-wt），其次是FHL（2至87，平均31 gm-wt），FDB装置产生的张力非常小（1至20，平均6 gm-wt）。Swett和Olson的FDL样本（108个单位）显示张力范围为0.3至100 gm-wt（平均10 gm-wt）。大的PL单位是有利的，有力的相位输入的数字在运动过程中，并在保持PL的额外作用，作为一个踝关节exstensor。FDB单元的低输出力对于在姿势的细微调整期间对手指的离散输入是最佳的。我们建议，较大的FHL快速收缩单位主要用于运动中所需的有力的手指屈曲和相位突出的爪子，而占主导地位的小和缓慢的FDL收缩单位用于持续的爪子突出。
The relation between muscle action and the mechanical properties of motor units has been explored in the main digit flexors of the cat hind limb: plantaris (PL); flexor digitorum brevis (FDB); flexor hallucis longus (FHL); and, flexor digitorum longus (FDL). General observations on muscle action revealed that PL is an ankle extensor as well as a digit flexor. PL and FHL were shown to be the major force contributors to digit flexion with FDL playing a lesser but still significant role.The mechanical properties of PL, FHL and FDB motor units were studied by noting twitch and tetanic tensions produced by electrical stimulation of single alpha axons, functionally isolated from the ventral root filaments. These data were compared to similar data reported by Olson and Swett (1966) for flexor digitorum longus (FDL). Our sample (114 PL, 60 FDB and 124 FHL units) disclosed that PL, FDB and FHL have units of uniformly fast contraction times (means 22, 27 and 27 msec respectively). PL units developed the most tetanic tension (3 to 160, mean 62 gm‐wt) followed by FHL (2 to 87, mean 31 gm‐wt) with FDB units producing very little tension (1 to 20, mean 6 gm‐wt). Swett and Olson's FDL sample (108 units) showed tensions ranging from 0.3 to 100 gm‐wt (mean 10 gm‐wt).A division of labor among the four muscles is proposed. The large PL units are advantageous for forceful phasic inputs to the digits during the locomotion and in keeping with PL's additional role as an ankle exstensor. The low output forces of FDB units are optimal for discrete input to the digits during subtle adjustments of posture. We propose that the larger fast contracting units of FHL are used primarily for forceful digit flexions required in locomotion and for phasic protrusion of the claws while the predominately small and slow contracting units of FDL are used for sustained claw protrusion.