是什么引起了下腰痛？（三）

今天接着聊下一部分

椎骨终板骨折

身体上椎骨并不只是一个坚硬的骨头，如果从椎体的横切面你实际上可以看到一种像海绵一样非常复杂的树枝状结构叫做骨松质，复杂的排列造就了一种结实的架构来支持骨骼，使得骨头有能力支持重量并且抵抗外部冲击防止骨折。

就像肌肉一样，骨头可以应对那些你在力量训练中出现的主动或者被动的负荷以及负荷的频率。例如，在正确的训练周期下进行力量训练会让脊柱慢慢适应，并且椎骨中的骨小梁会随着时间慢慢变粗，这就是为什么与普通人相比精英运动员拥有更高的骨密度的原因。

在这种适应性的过程中，记住也会慢慢适应一些微骨折，Dr. Stuart McGill 就说过几乎所有的精英运动员都有或多或少的微骨折。

这些微骨折通常从由椎骨体表面和软骨构成的分开椎骨和椎间盘的终板上开始的，终板有两个功能。首先能承受施加在椎骨上的负荷，并且阻止椎间盘里的髓核渗漏进上面的骨头，第二，它又足够的柔软且疏松多孔能够使营养物质和血液渗进出下方的椎间盘。

当椎体上有压力时，终板会伸展到他所覆盖的骨头上（就像用塑料袋包裹着碗一样），当压力过大最终会导致终板破裂。

如果在过度负重之后给予时间适应这个过程，那么身体会适应并用更结实的骨头代替微骨折。这就像你手上的老茧使手保持更结实，更能适应握紧杠铃一样。但是如果恢复的时间不够（例如在没有进行低强度的训练周，就进行更高强度的背部练习）持续施加在脊柱上的压力会不断累积导致越过极限点，导致微骨折变成更严重的问题。

小关节损伤

另一个会导致腰痛的问题是脊柱两侧叫做关节突关节的小关节受损，已经有研究表明15%-40%的长期腰痛是由小关节受损导致的。

那么这里是怎么受伤的呢？

这更像是一个套在手上非常紧的手套，每一个关节突关节都被结实的关节囊所包绕，关节囊被高度神经支配，也就是说关节囊周围有很多的神经穿过，帮助感受脊柱的位置、活动和疼痛。和椎间盘膨出相比，关节突关节损伤并不是由一次特殊的损伤那个引起的，而是由长期重复的压力和微小的损伤引起。

有趣的是，在脊柱的不同水平位置，关节突关节的形状是不一样的，有一些可以限制过度的旋转幅度，而有一些却是用来限制屈曲和伸展的。

这样的话，关节突关节就可能会在不同的运动中受到损伤。比如，在脊柱过度伸展的时候大量的压力会施加在下腰部的小关节突上关节上，这样就会牵拉到周围的关节囊，如果身体长期处于这个这种姿势，就会导致小关节受刺激，以及周围的关节囊出现疼痛，最终导致关节炎。

研究表明，小关节突关节炎既可以由屈曲，也可以由伸展引起。比如一个举重运动员的臀部灵活性不均衡，当他准备举起较大重量，并且在大重量负荷下身体呈现屈曲时，臀部不均衡的灵活性会导致骨盆轻微的旋转，使下腰部关节突关节受到过度的牵拉，如果这种问题不解决，长时间之后技术上的问题就会引起关节突关节囊的刺激，并有可能导致疼痛。

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