What causes shoulder pain?

什么原因导致了肩痛？

Shoulder pain is a common ache in the U.S.: By some estimates, as many as 67% of people experience shoulder discomfort¹ at some point over the course of their lives. The most mobile joint in your body, the shoulder is made up of bones held in place by muscles, tendons, and ligaments. They're all designed to work together to allow the shoulder to move freely in many different directions. This allows you to do everything from raising your arms over your head to throwing a baseball and scratching your back. "Unfortunately, this mobility² comes at the expense of stability," and that leaves the shoulder vulnerable to injury, says Clifford Stark³, medical director of Sports Medicine at Chelsea in New York City. Factor in the wear and tear of everyday life and it's easy to see why you're shouldering so much pain.

在美国，肩痛是常见的症状。据估计，多达67%的人会在一生中的某个时刻肩痛。肩膀是人体最活跃的关节，由骨头、肌肉、肌腱和韧带组成。这些成分注定要一起运作，这样肩膀才能在各个方向上自由移动。因此你能抬手越过头顶扔棒球、还能挠背。"不幸的是，这种移动是以稳定为代价的，"导致肩膀很容易受伤，纽约市切尔西运动医学的医疗总监克利福德·斯塔克说道。日常生活中，磨损肩膀的因素很多，因此你的肩膀为什么这么痛也就不言自明了。

You'll need to consult your doctor for a formal diagnosis⁴ of your shoulder pain. That visit will include a physical exam, and possibly an X-ray, MRI, or ultrasound, or you may even do a physical therapy right off the bat, Dr. Stark says.

你需要咨询医生，让他/她给你做正式检查。包括身体检查，可能还要做X光、磁共振成像或超声波，或者你甚至可以立马做个物理治疗，斯塔克医生说道。

Of all the reasons you can have shoulder pain, injury to your rotator cuff⁵ is the most common-in a recent study, two-thirds of people with shoulder pain had a rotator cuff problem. A group of muscles and tendons that attach to the bones of the shoulder joint, the rotator cuff keeps the ball of your upper arm bone centered in your shoulder socket⁶ and also helps you raise and rotate your arm.

肩痛的原因很多，肩关节的肌腱套受损是最常见的原因--在最近的一项研究中，三分之二肩痛的人都有这个问题。肌腱套是附着在肩关节骨头上的一组肌肉和肌腱，能使上臂骨头的球部保持在肩窝的中心，同时还能帮助你抬胳膊、旋转胳膊。

Doing the same motion over and over again can lead to inflammation of the rotator cuff tendons, also called tendonitis, which can cause shoulder pain. "The rotator cuff is like a tire-with aging or frequent use it gets thinner and thinner and eventually wears down," says Robert Gotlin, a sports and spine⁷ physician in NYC and an associate professor of rehabilitation⁸ medicine and orthopedics at the Icahn School of Medicine at Mount Sinai. With tendonitis, shoulder pain is often mild at first and only noticeable when you move the joint; after a while, they can become more severe and occur all the time.

一次又一次做同样的动作会导致肌腱套发炎，也被称为腱炎，从而导致肩痛。"肌腱套就像轮胎一样--老化或经常使用会导致其越来越薄，最终会被磨损，"纽约市的运动和脊椎医师、西奈山伊坎医学院康复医学和矫形外科部门的副教授罗伯特·戈德林说道。在患有腱炎的情况下，肩痛刚开始的时候都是轻度的，只有当你移动关节的时候才会有痛感；一段时间后，这些症状就会越来越严重，经常会让你疼的欲罢不能。