“指伸肌腱终腱-止点系统”与锤状指形成原因的探讨

Further research of stress analysis on terminal extensor tendon-endpoint system and mallet finger formation

目的：通过对指伸肌腱终腱止点及末节指骨的解剖学观测，以物理力学方法对锤状指的形成原因做进一步的探讨。方法在成人新鲜尸体手指标本上，通过模拟手术，对指伸肌腱终腱止点及末节指骨的结构特点进行应用解剖学观测，用物理力学原理对指伸肌腱终腱及末节指骨进行受力分析。结果指伸肌腱终腱止点呈浅帽状被覆于末节指骨基底背侧的“舌”形骨嵴顶端，远侧指间关节侧面观呈规则的圆弧形，末节指骨在屈伸肌腱的牵拉下围绕一个固定的轴心在中节指骨头表面做屈伸运动；终腱或舌形骨嵴在手指纵轴线处受力最大，在垂直于手指纵轴线处受力最小。结论“指伸肌腱终腱-止点系统”的命名利于对锤状指的形成原因作进一步解释，并为锤状指治疗方法的改进提供解剖学依据。

Objective Through anatomic observation of terminal extensor tendon endpoint and phalangette, make further research on pathogeny of mallet fingers by physical mechanical approach. Methods On finger specimen of fresh adult corpse, through imitative operation, carry out applied anatomic observation on structural characteristics of terminal extensor tendon endpoint and phalangette, as well as make stress analysis on terminal extensor tendon and phalangette with mechanical principles. Results The terminal extensor is covered at the tongue-shaped crest top of distal phalanx dorsal base in the shape of shallow cap. In lateral view, the distal inter phalangeal joint is in the shape of circular arc; under the traction of flexor and extension tendon, the phalangette makes flexion and extension movement on surface of middle phalanx centering on one fixed point; in extension position of phalangette, the stress upon terminal tendon and tongue-shaped crest is the smallest; along with the increase of flexion angle of phalangette, in the position of vertical axis, the stress reaches the maximum level. Conclusion Through anatomic observation and stress analysis on terminal extensor tendon endpoint and phalangette, it shows that, when the flexion angle due to finger sprain has reached certain extent, it is more easily to form mallet finger. Also, the paper will provide anatomic basis for improvement of therapeutic approach for mallet finger.