This is not actually one thing it is a group of muscles often mis-named by terms like rotatory cuff, rotator cup, and just plain rotater or roter. So no surprise that this group of muscles is complicated and misunderstood.
You may have heard people talking about having “torn their rotator cuff” and how they have a ‘bum shoulder’ now because of it. What are they really talking about, is four muscles of the shoulder Supraspinatus, Infraspinatus, Teres minor, and Subscapularis that may not be working optimally together. We believe there is not really a 'bum' anything just something that has room for improvement. We aren’t expecting you to remember or even be able to pronounce those words, but know that the rotator cuff is a group of four muscles. We remember them as the SITS group to keep them straight. The four muscles work together to stabilize the shoulder joint because the joint is very shallow, like a golf ball (arm bone) on a tee (socket). Each muscle on their own is responsible for producing a specific movement of the arm.
Your Supraspinatus muscle runs from the top of your shoulder blade out to attach on to the top of your arm bone. Its main purpose is to start the motion of lifting your arm up at your side.
Your Infraspinatus muscle sits below the supraspinatus on the shoulder blade. This muscle covers most of your shoulder blade and is shaped like a fan. It is larger and attaches right next to the supraspinatus on the arm. It’s main movement is to rotate your arm to touch the back of your head.
Your Teres minor is the smallest muscle in the SITS group. It sits below the Infraspinatus muscle also attaching to arm bone with the two muscles above. Because it is so small it only helps Infraspinatus with its main functions.
Your Subscapularis is the only member of the rotator cuff group that sits on the front side of your shoulder blade, between the blade and the rib cage. This is the largest of the SITS muscles, and it fans over the whole front of your shoulder blade and attaches on the exact opposite side of the arm bone compared to the other three muscles. It’s main function is to internally rotate your arm to put it in the sleeve of your coat, scratch your back or squeeze your arm to your side.
Rotator cuff injuries are quite common, many people find out later in life that they have a tear from many years ago without ever knowing it. However, some result from falling and jarring your arm and shoulder or during some other incident that involved a lot of pressure or force being pushed/pulled through your shoulder (e.g. seatbelt during a motor vehicle collision). These impacts can result in anything from minor injuries like partial muscle tears to more severe injuries like full thickness muscle tears or even, in rare cases, the muscle being torn completely off from where it attaches to the bone. Even where the muscle has been completely torn off, surprisingly surgery is almost never the first option and often it's not used at all. In all cases, appropriate exercises can help to re-train and strengthen the attached muscles back to full or near full function.
However, outside of the more traumatic injuries that can happen to your rotator cuff basic overuse/misuse injuries are much more common (e.g. tendinitis, bursitis or non-inflammatory injuries like Tendinopathies). Repetitive movements can often result in muscle and tendon irritation and you will often see athletes in sports like baseball, volleyball, and tennis having some problems with overuse injuries in their dominant shoulder. These injuries are most often not caused by inflammation meaning they are not an 'itis' like tendinitis instead they are a dysfunctional thickening of the tendon referred to as tendinopathy. With overuse/misuse injuries, the most effective treatment starts with the Physiotherapist diagnosing the areas for improvement in painful movements and muscle compensation patterns. The Physio will assess the extent of the injury and then create an appropriate treatment plan to stabilize, strengthen and return to activity.
Treatment for shoulders typically starts in the acute phase, days after the pain starts. In the acute phase treatments like massage therapy, acupuncture, soft tissue work, IMS (needling) and shoulder stabilizing exercises are often used. As the injury starts to improve, the treatment will shift into a more active approach where exercises are used to target the movement patterns that resulted in misuse in the first place.
Find a Physiotherapist and a Registered Massage Therapist, in your town, to help get you on the right track to getting back to the activities you love!