Mick J E, Reswick J B, Hager D L
J Hand Surg Am. 1978 Jul;3(4):333-41. doi: 10.1016/s0363-5023(78)80033-1.
To demonstrate in the cadaver model that the sequence of extension of the flexed metacarpophalangeal and proximal interphalangeal joints of the intrinsic-minus finger can be explained on the basis of moment ratios about these joints, the engineering concept of free body analysis was applied. Intrinsic-minus fingers, i.e., fingers of a cadaver in which all forces exerted by the intrinsic muscles were removed, were observed to hyperextend maximally at the metacarpophalangeal joint before extension of the proximal interphalangeal joint began. Mathematical calculation of moments provides an explanation of this sequence. This study confirmed that, when an equilibrium of forces at the hyperextended metacarpophalangeal joint is reached, the proximal interphalangeal joint is incompletely extended. These forces include: (1) the proximal pull of the extensor tendon; (2) the distal loading of the extensor tendon by the flexor tendons; (3) the force preventing spanning of the laminae.
为了在尸体模型中证明，基于围绕这些关节的力矩比，可以解释内收肌缺失手指的掌指关节和近端指间关节屈曲伸展的顺序，应用了自由体分析的工程概念。观察到内收肌缺失的手指，即去除了所有由内在肌肉施加的力的尸体手指，在近端指间关节开始伸展之前，掌指关节最大程度地过度伸展。力矩的数学计算解释了这个顺序。本研究证实，当掌指关节过度伸展达到力平衡时，近端指间关节并未完全伸展。这些力包括：（1）伸肌腱的近端拉力；（2）屈肌腱对伸肌腱的远端负荷；（3）防止薄片跨越的力。
