The pectoralis minor is a muscle that becomes easily shortened and tight due to many factors, including rounded shoulder posture, glenohumeral joint dysfunction,breathing dysfunction, and a variety of compensation patterns. It sits on top of the brachial plexus, and can therefore contribute to Thoracic Outlet Syndrome.

( 胸小肌很容易变的短缩与僵紧，原因有许多，包括圆肩姿势、肩盂肱骨关节异常、呼吸异常及各种代偿的模式。胸小肌位在臂神经丛的上方，因此造成胸廓出口症候群的发生。)

The pectoralis minor is located in an area of the shoulder with many other muscles, including the pectoralis major, biceps, deltoids, coracobrachialis, subscapularis, serratus anterior, and the latissimus dorsi.

( 胸小肌位在肩膀的区域中，这个区域也包含了其它的肌肉，包括胸大肌、肱二头肌、三角肌、喙肱肌、肩胛下肌、前锯肌及背阔肌。)

I find that clusters of muscles like this often can become dysfunctional due to poor biomechanics. This can lead to adhesions, facilitation/inhibition, and synergistic dominance. The pectoralis minor is often the overactive muscle in these compensation patterns.

( 由于欠佳的生物力学，这丛肌群时常发生异常的状况，导致沾黏、诱发/抑制及协同肌主配效应。而在这些代偿的模式中，胸小肌经常是过度活跃的情况。)

Rounded shoulder posture and forward head posture will cause the pectoralis minor to shorten. This action is called protraction and is opposed by the muscles of retraction. These include the middle trapezius and the rhomboids. Commonly the pectoralis minor becomes facilitated and the middle trapezius becomes inhibited. Release of the pectoralis minor followed by strengthening of the middle trapezius can be very effective in these cases.

( 圆肩姿势及前位头部错姿将导致胸小肌短缩，这个动作称为前突，会影响到中斜方肌与菱形肌。普遍来说，胸小肌处于诱发状况下，中斜方肌会受到抑制。在这个情况下，进行中斜方肌的训练之前，先进行胸小肌的放松，会得更非常好的效果。)

Because the pectoralis minor rounds the shoulder, it is opposed by the latissimus dorsi which moves the shoulder back and down. Again, release of the pectoralis minor followed by strengthening of the latissimus dorsi can be very effective.

( 胸小肌将肩膀往前拉动，而位在对侧的背阔肌则是将肩膀往后往下进行移动。同样的，在进行背阔肌的训练之前，先进行胸小肌的放松，效果会更好。)

The pectoralis minor is a downward rotator of the scapula and oftentimes involved in glenohumeral dysfunction. If it is facilitated, it can inhibit the serratus anterior, which contributes to upward rotation of the scapula. This can lead to impingement syndrome and sometimes winging of the scapula. The resultant scapular instability greatly contributes to shoulder joint dysfunction.

(胸小肌是一个肩胛骨的下转肌群，经常涉及肩盂肱骨关节异常。若它处于诱发状况，会抑制肩胛骨上转肌"前锯肌"的作用，导致夹击症候群(Impingement Syndrome)，而有时可能造成肩胛骨内缘外掀的情况，这种情况所产生不稳定肩胛骨会引起肩关节异常的状况。)

The pectoralis minor is also an internal rotator of the humerus. When facilitated it can inhibit the external rotators of the humerus, including the long head of the biceps, the posterior deltoid, and the infraspinatus.

( 胸小肌也是肱骨的内转肌。当它处于诱发的状况下，会抑制肱骨的外转肌群，包括肱二头肌长头、后三角肌及棘下肌。)

A common shoulder injury that occurs from this is that the long head of the biceps comes out of its groove and moves medially towards the short head of the biceps. Release of the pectoralis minor followed by relocation of the long head of the biceps tendon is very effective in these cases.

( 一个普遍肩膀伤害的发生就是来自于胸小肌处于诱发的情况，肱二头肌长头(long head of the biceps)脱离其腱沟，而往肱二头短头(short head of the biceps)的内侧进行移动。在这个例子中，先放松胸小肌之后，接着再进行肱二头肌长头的重新定位会非常有效率。)

The pectoralis minor also contributes to kinetic chain dysfunctions. For example, in the front line, the pectoralis minor often inhibits the psoas. In the diagonal line, it can inhibit the contralateral psoas. This is a factor in gait dysfunction.

( 胸小肌也会引起动力鍊异常的情况。举例，在前侧线，胸小肌经常抑制腰肌。在对侧线，它会抑制对侧的腰肌。这是步态异常其中一个因素。)

Also in gait it can inhibit the backward swing motion of the contralateral arm and the backward swing of the ipsilateral leg. Right thoracic rotation can be inhibited by the right pectoralis minor because of its contribution to internal rotation.

( 在步态中，胸小肌会抑制对侧手臂后摆的动作及同侧脚的往后摆动。右胸腔旋转会被右侧的胸小肌给抑制住，因为胸小肌步及内转的动作。)

这篇文章其实山姆很早就看过，但当时还不了解什么是“Synergistic Dominance(协同肌主配效应)”，但在知道协同肌主配效应之后，再重新回来看这篇文章，疑问则慢慢的解开了。但有些的状况，山姆伯伯还是不懂，但等有遇到时，或许就能懂得更多啰。

图片来源：American Family Physician

文章来源：山姆伯伯工作坊