De Palma L, Tulli A
Istituto di Clinica Ortopedica, Università Cattolica del S. Cuore, Roma.
Arch Putti Chir Organi Mov. 1991;39(2):239-47.
The authors conducted a macroscopic anatomical study of the metatarsophalangeal joints of the middle toes in order to add to our knowledge of the anatomy and physiology of this structure. Anatomical observations reveal the foot's lack of transverse ligamentous formations (as the sagittal bundle in the hand) connecting the extensor tendon to the glenoid plate. Consequently, the containment of the extensor tendon above the metatarsophalangeal joint is considerably less stable in the foot than in the hand, since it is entrusted to the posterior portion of the interossei muscles and the deep and superficial retinacula (all formations which run in a prevalently oblique direction). Hyperextension of the metatarsophalangeal joint causes the posterior portion of the interossei muscles, bound to the extensor tendon, to slide proximally, straightening the fibers and loosening the structures that stabilize the extensor tendon. The tendon can then easily shift in a lateral direction with respect to the rotation axis of the metatarsophalangeal joint, acquiring a valgus action. Even though the metatarsophalangeal joint is equipped with strong collateral ligaments, the valgus action of the extensor tendon eventually overcomes the resistance of both these and the weaker connections to the plantar aponeurosis of the foot and the extensor tendons. In conclusion, the lack of structures to provide passive stabilization of the extensor tendon in the metatarsophalangeal joints of the toes makes the foot particularly susceptible to multiple-toe deformity.
作者对中趾的跖趾关节进行了宏观解剖学研究，以增进我们对该结构解剖学和生理学的了解。解剖学观察表明，足部缺乏将伸肌腱与关节盂板相连的横向韧带结构（如手部的矢状束）。因此，与手部相比，足部跖趾关节上方伸肌腱的容纳稳定性明显较差，因为它依赖于骨间肌的后部以及深浅两层支持带（所有结构主要沿斜向走行）。跖趾关节的过度伸展导致与伸肌腱相连的骨间肌后部向近端滑动，使纤维伸直并放松稳定伸肌腱的结构。然后，肌腱相对于跖趾关节的旋转轴很容易向外侧移位，产生外翻作用。尽管跖趾关节配备了强大的侧副韧带，但伸肌腱的外翻作用最终会克服这些韧带以及与足部跖腱膜和伸肌腱较弱连接的阻力。总之，脚趾跖趾关节中缺乏为伸肌腱提供被动稳定的结构，使得足部特别容易出现多趾畸形。
