Kaufman K R, An K N, Litchy W J, Cooney W P, Chao E Y
Department of Orthopedics, Mayo Clinic/Foundation, Rochester, MN 55905, USA.
Clin Biomech (Bristol). 1999 Feb;14(2):141-50. doi: 10.1016/s0268-0033(98)00058-8.
The purpose of this study is to quantify the electrical activity of the thumb muscles responsible for the production of force in different directions of thumb movement.
The isometric forces and electromyographic activity generated by seven thumb muscles were measured on five normal healthy test subjects.
The thumb is very important for proper hand function. Presently available electromyographic studies of the thumb muscles provide only limited information. Most thumb muscles have more than one function. Additional studies are required to carefully examine and confirm the in-vivo relationship between the thumb muscle electromyogram and mechanical output.
The direction and magnitude of the force vector generated at the interphalangeal joint and the relative electrical activity were obtained for eight directions of thumb action. The regions of function were defined for the abductor pollicis brevis, opponens pollicis, flexor pollicis brevis, adductor pollicis, flexor pollicis longus, extensor pollicis longus, and the abductor pollicis longus. Data was collected during voluntary isometric contraction, both before and after blocking the median nerve at the wrist.
The highest force production was obtained during flexion. The region of maximal muscle electrical activity varied for each muscle studied. The areas of maximal in-vivo muscle activity agreed with the moment arm data reported in the literature. The median nerve block eliminated the ability to produce force in abduction.
This study has demonstrated that by combining electromyographic measurement and biomechanical analysis it is possible to confirm the relationship between in-vivo thumb muscle function and muscle mechanics in a novel manner. The findings of this study indicate the importance of the local anatomy in controlling the direction of force production.
本研究的目的是量化负责在拇指不同运动方向产生力的拇指肌肉的电活动。
在五名正常健康受试者身上测量了七块拇指肌肉产生的等长力和肌电图活动。
拇指对于手部正常功能非常重要。目前可用的拇指肌肉肌电图研究仅提供有限的信息。大多数拇指肌肉具有多种功能。需要进一步的研究来仔细检查和确认拇指肌肉肌电图与机械输出之间的体内关系。
获取拇指在八个动作方向上在指间关节产生的力矢量的方向和大小以及相对电活动。定义了拇短展肌、拇对掌肌、拇短屈肌、拇收肌、拇长屈肌、拇长伸肌和拇长展肌的功能区域。在腕部阻断正中神经之前和之后的自愿等长收缩期间收集数据。
在屈曲过程中获得了最高的力产生。所研究的每块肌肉的最大肌肉电活动区域各不相同。体内最大肌肉活动区域与文献中报道的力臂数据一致。正中神经阻滞消除了外展时产生力的能力。
本研究表明，通过结合肌电图测量和生物力学分析，可以以一种新颖的方式确认体内拇指肌肉功能与肌肉力学之间的关系。本研究结果表明局部解剖结构在控制力产生方向方面的重要性。
