Shoulder Impingement: When the Rotator Cuff Has No Room to Move

Diagram of subacromial impingement

You lift your arm to hang up your jacket, to do your hair, or to serve in padel, and there it is: a sharp pain in the upper, outer part of the shoulder right in the middle of the movement, at around 90 degrees. You rest for a few days, it improves a little, you go back to your activity and the pain comes back. It's one of the most common reasons people come to shoulder physiotherapy, and it has a specific clinical name: subacromial impingement syndrome.

What's actually happening in there?

Under the acromion, the highest part of the shoulder blade, there's a narrow space through which several rotator cuff tendons pass, especially the supraspinatus tendon. If we think of the tendon as the transmission cable carrying the muscle's force to the bone, impingement is what happens when that cable loses the room it needs to move inside its tunnel: it rubs, becomes irritated and, over time, can become inflamed (including the subacromial bursa) or the tendon itself can degenerate — something many people simply call "rotator cuff problems" or "supraspinatus tendinitis" in consultation, even though the supraspinatus isn't the only tendon that can get pinched against the acromion. That's why the pain mainly appears when lifting the arm above the head or rotating it inward. Does it bother you when you're sitting in the driver's seat and reach to grab something from the back seats? That's the typical movement that triggers pain in this condition.

Why does real-time ultrasound change the diagnosis?

An X-ray or an MRI shows the shoulder still, frozen at a single moment. Impingement, on the other hand, is by definition a movement problem: the tendon gets pinched at a specific angle of the motion, not the whole time. That's why at KINEO Benidorm we rely on real-time musculoskeletal ultrasound: it lets us see the tendon sliding under the acromion while the patient actually lifts the arm, check for fluid in the subacromial bursa, assess the thickness and structure of the tendon, and rule out a partial tear — all in the same visit and with no radiation. Chema, who specialises in musculoskeletal physiotherapy with the shoulder as his area of focus, carries out all the ultrasound assessment of this joint at KINEO Benidorm. You can find out more about how we use this test on our Shoulder Ultrasound page.

So what now? The approach isn't "total rest"

Treating impingement usually isn't about stopping moving the shoulder, but the opposite: re-educating how it moves. A well-designed physiotherapy plan works on motor control of the shoulder blade, which is also part of the problem when it doesn't properly stabilise the space the tendon passes through, together with progressive, dosed loading of the rotator cuff tendons so they adapt instead of staying irritated. In more advanced tendinopathies or with calcifications, once ultrasound has confirmed the exact stage of the problem, complementary tools such as shock wave therapy or invasive physiotherapy may be considered. There are no universal guarantees: every shoulder and every history is different. But there is an evidence-backed approach for this condition: dosed exercise and decisions guided by imaging, not guesswork.

If you notice that characteristic sharp pain when lifting your arm, or you've had a shoulder that "just won't heal" for a while, book an appointment at KINEO Benidorm. With a clinical and ultrasound assessment in the same visit, we can tell you, based on data rather than guesswork, what's going on with your shoulder and what the next step should be.