Jim Johnson, PT
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                So what's a rotator cuff anyway?

     Well, first a little anatomy.  Your shoulder is a ball and socket joint that is very mobile, yet very prone to coming out of place due to its shallow socket. However, while its true that Mother Nature has put our shoulders at a slight mechanical disadvantage, it didn't leave us totally helpless either.  Instead of giving the shoulder a nice deep socket, like the hip joint, or lots of strong ligaments to hold the bones together, we've got the next best thing - powerful support from the rotator cuff muscles. 

     Individually, each of the four rotator cuff muscles have their own jobs.  Some help roll the shoulder in, some help roll the shoulder out, and so on. But when all the rotator cuff muscles work together and contract at the same time, their combined pull helps keep the shoulder's ball and socket joint firmly in its place. 

     Now there are four rotator cuff muscles, the supraspinatus, infraspinatus, teres minor, and subscapularis, and when these muscles all contract AT ONCE, the net result is that the upper arm bone gets pulled snuggly towards the shoulder blade, thus firmly locking the "ball" into the "socket." 

     And when exactly does this happen, the rotator cuff muscles "kicking in" and contracting all at once to stabilize the shoulder joint?  Well, according to the latest research, it occurs immediately before a person starts to move their shoulder around.  For example, if you were to reach out right now and wave to someone, your rotator cuff muscles will contract the very instant BEFORE your arm actually starts to move.  In this way, the shoulder joint starts out in a safe position and is held tightly in place as you go about using it.  Pretty neat, huh?

    Scientific-minded readers will also be glad to know that the research has confirmed the stabilizing role of the rotator cuff muscles. A study published in the peer-reviewed journal Clinical Biomechanics involved recording the EMG activity of people's shoulder muscles as they were asked to perform certain motions (David, 2000).  Sure enough, researchers found that a "pre-setting" of the rotator cuff muscles occurred before any shoulder motion actually took place. 


                                                                                Jim Johnson, PT
 

            Strong Rotator Cuff = No Shoulder Pain 
     
Getting rid of pain through the use of strengthening exercises is a tried and true approach, and using it to fight shoulder pain is no exception. 

     A good example of this is a study published in the peer-reviewed journal Physical Therapy, that took sixty-six patients complaining of shoulder pain and aimed to get them better by improving the function of their rotator cuff muscles (Ginn 1997).

     Patients in this study were excluded if their pain was in both shoulders, due to an inflammatory disorder or cancer, coming from the back, or because of an accident. Past that, it really didn’t matter what the cause of the shoulder pain was in order for a patient to be included in the study, and in fact, some patients even had no diagnosis, meaning that the cause of their shoulder pain was unknown!

     Now here’s a few of the known diagnoses that patients DID walk into the study with:
  • tendinitis
  • rotator cuff tear
  • frozen shoulder
  • osteoarthritis
  • biceps muscle tear

     Typical of a randomized controlled trial, patients were put into either a treatment group or a control group. When reassessed one month later, follow-up results revealed that those who had restored the function of their rotator cuff muscles could move their shoulders with less pain, were more independent with daily personal care, and had a greater reduction in their shoulder symptoms. In stark contrast, the control group, which sat on a waiting list for a month without any treatment, got worse.

     According to the results of this randomized controlled trial, improving shoulder function by treating the rotator cuff muscles is quite an effective way to fight shoulder pain, even in cases where the cause is NOT obvious. 


                                                                                      Jim Johnson, PT


             What are the symptoms of a rotator cuff tear?

     Symptoms of having a torn rotator cuff can vary widely from person to person and it is never a good idea to say for sure that somebody has a tear based upon any one, single symptom.  Several studies have taken large groups of people with verified tears in their rotator cuff and evaluated how well their shoulders work (Duckworth 1999, Harryman 2003).  Interestingly, both studies drew the same conclusion: the symptoms of a rotator cuff tear can vary widely from one person to the other.  For example, some subjects said that they could lift eight pounds to their shoulder level or even throw a softball overhand twenty yards – while other subjects could not.

     Keeping all this in mind, there are some symptoms that people with documented rotator cuff tears frequently (but not always) report:

  • shoulder pain, commonly in the top, front, or side areas
  • shoulder weakness which can limit activities such as combing your hair, tucking in your shirt, or putting dishes away. Reaching up above the level of the shoulder can be particularly troublesome.
  • pain at night, especially when sleeping on the same side as the affected shoulder             
                                                                                 Jim Johnson, PT        
                                                     

        So how do doctors know if I’ve torn my rotator cuff?

     Figuring out if you’ve torn your rotator cuff usually starts out with a history and physical or “H and P” in medical terminology.  This would be where your doctor asks you questions and has a look at your shoulder.  In many cases, this includes special tests that involve putting your shoulder in different postions to try and put stress on the rotator cuff.  From all of this, it is impossible to be absolutely sure that you have a tear, although such an exam can lead to a strong suspicion.

     Next, depending on your situation, additional imaging tests may be considered in order to get a “picture” of what’s going on. Here are some common ones that doctors use:

  • an x-ray, which looks mainly at the bony structure of your shoulder
  • an MRI, which looks at the soft tissues (such as tendons and muscles)
  • an ultrasound, which uses sound waves to create a picture of the inside of your shoulder
  • an arthrogram, where a special dye is injected into your shoulder joint and then x-rays are taken. A normal rotator cuff should contain the dye within the joint, while a torn cuff allows dye to leak into the surrounding tissues.

     After all is said and done, the information from the history and physical, as well as the results of any ordered imaging tests, are all put together to try and rule in or rule out a rotator cuff tear.

     While this is a typical order of events that many people will go through in order to arrive at a diagnosis, this may vary depending on your particular doctor and situation.
                                                                                       Jim Johnson, PT



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