I’ve been dealing with my own shoulder impingement issues lately as well as working with a couple of patients which has motivated me to learn more about shoulder pain and shoulder health.

And since shoulder pain is so common…

“Shoulder pain is highly prevalent within the general population, second only to lower back pain. Studies suggest that shoulder impingement syndrome (SIS) is the most common cause of shoulder pain ” [1-4]

…I thought I’d write about it.

Who Commonly Gets Shoulder Pain/Impingement

Repetitive activity at or above the shoulder during work or sports represents the main risk factor for SIS. As with many shoulder disorders, increasing age also predisposes to SIS [4,5]. SIS is common among athletes who participate in overhead sports [6-11]. These sports may include swimming, throwing, tennis, weightlifting, golf, volleyball, and gymnastics [12]. Overhead work activities that can increase risk for developing SIS include painting, stocking shelves, mechanical repair, hair stylists, etc, [3,13].

Don’t Be So Surprised About Your Shoulder Pain

I think people generally expect their body to work for them when they do physical activity.  It’s boring to work on prehab and preparing for physical activity, so I don’t blame people for not wanting to do it.  The problem is that if you’re relatively sedentary or sit hunched over a desk all day, your body has adapted to those tasks and will take time to adapt to greater demands you might want to place on it.  Active people can also adapt to specific repetitive activities that may promote movement dysfunction.  When they try to change it up and do something different, they get injured and don’t understand why because they think they are in “good shape” and “fit”.

So how is a person supposed to know how to move correctly and have any idea what their movement dysfunctions are that leave them prone to injury?  Unfortunately, it’s difficult to know these things without spending a lot of time studying, learning, and re-learning.   Which is great if it’s your career but much harder when you have other things to worry about.

I’m humbled to say that my recent CrossFit endeavors have exposed several of my own movement limitations and exposed me for not responsibly working on my shoulder health and function.

Addressing the Underlying Cause of Shoulder Pain

To address shoulder pain, we have to start with a global perspective, realizing that  moving our arm to the overhead position requires several synchronized joint and muscle actions.  The furthest we can narrow our area of focus down includes the thoracic spine, scapula, gleno-humeral joint, and the related musculature.

First, take a look at all the movement and range of motion that the scapula SHOULD have.  Maybe you didn’t even really know it was back there.  Spend some time looking in the mirror. Get acquainted with this area, seeing how much it moves and gaining some control over it.

Scapular movement is very important in moving your arm.

The Thoracic Spine and Scapular Connection

Shoulder pain from a movement dysfunction perspective starts with addressing thoracic spine mobility, scapular stability, and motor control.  Of course, you also need good mobility of the glenohumeral joint which can often be inhibited by tight pecs and lats, but I think that’s of secondary importance at this point.

The humerus and gleno humeral joint attach to the scapula which rides on the thoracic rib cage which is intimately tied to the thoracic spine. The picture below shows the importance of the scapula being able to ride down the thoracic cage while simultaneously having enough thoracic extension to get the scapula in the necessary plane.  Notice the thoracic curvature and position of the scapula.

Typically  overhead pressing movements are the pain producing culprit and I’ll explain why.  When we put our arms overhead we reduce the subacromial space which the supraspinatus muscle passes through.  When you put a bar in your hands and add that internal rotation, the subacromial space closes even more.  Add a lack of scapular stability and being able to keep the scapula down and back and the humerus shifts up in the joint and closes the subacromial space even more.  This irritates the supraspinatus muscle and can lead to fraying and eventually rupture if continued.  Overhead pressing can also put significant compressive forces on the discs in your neck, especially if you look like the picture on the right above when you put your arms up.  Common symptoms of an irritated disc include neck stiffness and discomfort and potentially some associated pain into your upper back/shoulder.

The next picture shows how not all sub-acromial spaces (the supraspinatus muscle passes through here) are created equal.  There are variations in the shape of the acromion process that you are born with and can’t do anything about.  It’s possible that some people may always have trouble with much overhead loading.  Degenerative changes like “bone spurs” can also contribute to making the space smaller.  The only way to know what your acromial space looks like would be to see it on imaging like an x-ray or MRI.  (These are 2 pictures of the same thing. There’s just three types, not six.)

As I said before, raising your arms overhead tends to decrease the space, adding internal rotation closes it more (hands overhead with palms facing forward).  The humerus (upper arm bone) can also ride up in the socket and further reduce the space.  This is the part we have the most control over.  With thoracic spine extension, we allow the scapula the opportunity to get in the correct place.  And with scapular stabilization and motor control, we can affect the humerus’ position in the socket and thereby maximize acromial space for the supraspinatus muscle.

On the front side of our body, we have the pectoralis minor which attaches to the coracoid process of the scapula.  If this muscle is overly tight, (and it commonly is) it will make it difficult for the scapula to depress and retract into proper position for overhead movements.

One last image I want to include is the actual capsule of the gleno-humeral joint.  I’ve been talking about the active structures of the shoulder but passive structures like the capsular ligament also contribute to optimal shoulder health and stability.  It can be damaged and torn and will often “click”, “pop”, or “clunk”  after that has occurred.  This is also referred to as a labral tear.  The capsule can also be stiff or tight in a particular direction.  It is not uncommon for the posterior portion of the capsule to be tight and stiff.  This tends to lead to anterior and superior migration of the glenohumeral joint, again creating a higher likelihood for impingement, dysfunction, and pain.

If you have damaged these ligaments then it is EVEN MORE important to keep this entire area “fit and functional.”

Now that you know how this area works or SHOULD work, I’ll cover corrective strategies in part 2.

Here’s a helpful video to further show how this impingement takes place:

Sources:

1. Michener LA, Walsworth MK, Burnet EN. Effectiveness of rehabilitation for patients with subacromial impingement syndrome: a systematic review. J Hand Ther 2004; 17:152.
2. Schröder J, van Dijk CN, Wielinga A, et al. Open versus arthroscopic treatment of chronic rotator cuff impingement. Arch Orthop Trauma Surg 2001; 121:241.
3. Faber E, Kuiper JI, Burdorf A, et al. Treatment of impingement syndrome: a systematic review of the effects on functional limitations and return to work. J Occup Rehabil 2006; 16:7.
4. van der Windt DA, Koes BW, de Jong BA, Bouter LM. Shoulder disorders in general practice: incidence, patient characteristics, and management. Ann Rheum Dis 1995; 54:959.
5. Schröder J, van Dijk CN, Wielinga A, et al. Open versus arthroscopic treatment of chronic rotator cuff impingement. Arch Orthop Trauma Surg 2001; 121:241.
6. Faber E, Kuiper JI, Burdorf A, et al. Treatment of impingement syndrome: a systematic review of the effects on functional limitations and return to work. J Occup Rehabil 2006; 16:7.
7. van der Windt DA, Koes BW, de Jong BA, Bouter LM. Shoulder disorders in general practice: incidence, patient characteristics, and management. Ann Rheum Dis 1995; 54:959.
8. Ardic F, Kahraman Y, Kacar M, et al. Shoulder impingement syndrome: relationships between clinical, functional, and radiologic findings. Am J Phys Med Rehabil 2006; 85:53.
9. Meister K. Internal impingement in the shoulder of the overhand athlete: pathophysiology, diagnosis, and treatment. Am J Orthop (Belle Mead NJ) 2000; 29:433.

• Lombardo SJ, Jobe FW, Kerlan RK, et al. Posterior shoulder lesions in throwing athletes. Am J Sports Med 1977; 5:106.
• Walch, G, Boileau, P, Noel, E, Donell, ST. Impingement of the deep surface of the supraspinatus tendon on the posterosuperior glenoid rim: an arthroscopic study. J Shoulder Elbow Surg 1992; 1:238.
• Bennett, GE. Shoulder and elbow lesions of the professional baseball pitcher. JAMA 1959; 117:510.
• BENNETT GE. Elbow and shoulder lesions of baseball players. Am J Surg 1959; 98:484.