By Erin Galway, Registered Physiotherapist
Shoulder pain is a very common issue seen in orthopaedic clinics. Many patients who end up with shoulder pain have never actually injured their shoulder but one day they start to notice pain with certain movements. This pain continues or may even increase after stopping most of their activities. To understand why this happens and to successfully treat shoulder pain you need to understand the dynamic and complex relationship between the rotator cuff (RC) muscles and the shoulder blade (scapula) in providing a stable base during movement. Below I list and explain the 5 things you need to know about the scapula, shoulder pain and treatment.
- The muscles that attach to the scapula are needed to provide stability during movement You may not know this but just to raise your arm overheard requires a lot of coordination of several muscles to keep your scapula in the right position. This does not include the other muscles that contract just to raise the arm itself. As you move your arm the three portions of the trapezius (upper, middle & lower) and the serratus anterior all contract to pull on the scapula to move it upwards. Even as you lower your arm new muscles kick in to keep the scapula in the proper position. Altered timing or weakness of any of these muscles can lead to a change in position of the scapula during rest and during movement. For example, your scapula may not rotate fully upwards, it may sit forward or it may “wing” (where your shoulder blade protrudes from your back).
- Proper scapula position means the Rotator Cuff (RC) muscles function properly The RC muscles are a group of 4 muscles (supraspinatus, infraspinatus, subscapularis and teres minor) that connect the arm to the scapula. Their goal is to work together to keep the arm centred in the shoulder joint. In order for these RC muscles to work properly the scapula needs to be stable when moving your arm. As mentioned above this is achieved from the precise sequencing of all muscles that attach onto the scapula. When all muscles are working properly this will allow for a large range of motion at the shoulder. When the scapula is not stable more tension is placed on one or more of the RC muscles during movement, irritating tendons and over time leading to pain & weakness.
- Shoulder joint position affects the stability of the scapula In addition to the position of the scapula and the effect on the RC muscles, the position of the shoulder joint when raising your arm can play a role in scapular stability and shoulder pain. For example, the shoulder may sit too far forward of the body as well as too far upwards in the joint leading to a decrease in range of motion of the joint, improper movement of the scapula and weakness of the RC muscles. Now as you raise your arm overhead there is less space for the tendons of the RC muscles to move creating impingement of the tendons & pain.
- Symptoms can be decreased by repositioning the scapula and shoulder joint The importance of the scapula and shoulder joint position can be demonstrated in clinic by appropriately repositioning them while the patient raises their arm and observing their symptoms. By manually repositioning the scapula or the shoulder joint it can unload certain structures decreasing pain and increasing the range of motion. This is a simple test that tells the clinician and patient that treatment of shoulder pain should involve exercises that address the position of the scapula and shoulder joint.
- Treatment of shoulder pain begins with dynamic stabilization When treating the shoulder the focus should be providing static and dynamic stability of the scapula and shoulder. As a physiotherapist, our focus is on observing the quality of the movement of the shoulder joint and identifying the structures at fault. A combination of exercises and manual therapy is used to address the scapula stability and alignment of the shoulder, reducing shoulder pain and restoring proper movement patterns.
To raise your arm overhead involves a complex relationship between the RC muscles and the scapula. This relationship allows for an incredible amount of mobility but frequently at the expense of stability. Addressing the quality of shoulder movement is important in decreasing shoulder pain. If you have shoulder pain with certain movements or pain that persists long term it is possible that the quality of the movement is poor and the position of your scapula and shoulder joint needs to be addressed in treatment.
Erin is a graduate of McMaster University’s Masters in Physiotherapy program. Erin also has completed courses in advanced manual therapy, Fascial Stretch Therapy and has experience as a sports & conditioning trainer. Erin has worked with acute & chronic musculoskeletal injuries as well as acute stroke patients.