Injuries: Shoulder Impingement

This is part of a series about Injuries In Yoga.

Two common injuries in yoga happen in the shoulder. One is in the front of the shoulder---the biceps tendon---which we will address next time. The other is in the top of the shoulder, called impingement. It happens when the arm lifts up high; the arm bone can bump against the edge of the shoulder blade, called the acromion, and damage the tendon there.

​Let's start with a little anatomy. The supraspinatus muscle is one of the four rotator cuff muscles. It is located on top of the shoulder blade, weaving underneath the acromion to attach to the arm bone (humerus). The supraspinatus ​is pictured in blue on the right.

​As the arm lifts up and to the side in flexion and abduction, the arm bone gets closer and closer to the acromion. The supraspinatus​ actually helps in this process, pulling the arm bone up. Generally, as the arm lifts, the shoulder blade will rotate to give space in the joint. But if the shoulder blade muscles like the rhomboids or trapezius are tight, or if we hold the shoulder blades toward the spine, the arm bone (humerus) can bump into the acromion and damage the tendon of the supraspinatus​. See the picture below.

HOW THIS CAN HAPPEN
​In yoga, this happens most often when we force the arms overhead. Think of any time you link your hands together and then try to straighten your arms using force. As pictured below, it happens in Half Moon Backbend, Half Moon Sidebend, Balancing Stick and Half Tortoise, among others. (It also happens in Downward Facing Dog.) When we force our arms to straighten overhead, we usually use the triceps, a muscle mainly of the elbow, to compel movement in the shoulder. This is where we get into trouble and impingement can happen. You will feel a 'pinching' sensation in the top and outside of your shoulder. This is the bones bumping into each other, damaging the soft tissue.

If the shoulders become injured this way, they will be painful whenever lifting the arms sideways, and the breathing exercise pictured at the top will cause pain.

Half Moon Backbend

Half Moon Sidebend

Balancing Stick

Half Tortoise

HOW TO HELP
The simplest and most effective way to avoid this injury is to not link your hands together. Just place them side by side without interlacing the fingers. Interlacing the fingers and forcing the arms straight overhead is the easiest way to create the injury. 

Or don't lift your arms overhead (pictured below left). Most postures can be done quite effectively without the arms overhead. All of the positions pictured above don't require the arms to get the primary benefit.

Alternatively, you can lift your arms forward and up (pictured below) instead of out to the side. This will help the shoulder blades move into the proper position and keep the shoulders healthy.

In the breathing exercise, pictured at the top, you can keep your elbows lower, not lifting them higher than the shoulders. This will prevent further irritation of this area.

To build strength in the area, postures like Full Locust will help (pictured below right). By pulling the shoulders back and together, we build strength in the back of the shoulder to help stabilize and balance the joint.

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CONCLUSION
The moral of the story is that we should be aware and careful when lifting the arms overhead, especially if we are gripping the hands together and straightening with force. If there is a 'pinching' sensation in the top of the shoulder, back off immediately. There is nothing there to 'stretch', and it is likely that we are impinging our supraspinatus tendon. Try adjusting your approach to the posture and using your shoulders a little differently.

Happy, healthy practicing.