The subscapularis muscle is the largest of the four rotator cuff muscles. It is responsible for internal rotation and adduction of the your arm at the shoulder. Most importantly, in conjunction with the other rotator cuff muscles, it is responsible for dynamic stabilization of the shoulder joint. The shoulder has less connective tissue structure than other major joints. The rotator cuff muscles act as a sort of dynamic muscle/ligament hybrid to stabilize the shoulder joint as you move. Of the important function of subscapularis is to provide dynamic restraint to the  back side of the shoulder joint.

Trigger points in your subscapularis cause pain in the back of the shoulder, and sometimes extending down the back of your arm. Referred pain can also develop on the back side of your hand, wrist, forearm.

Subscapularis trigger points are often involved with Frozen Shoulder Syndrome. They are frequently the foundation of an entire range of shoulder dysfunction.

Trigger points can be activated anywhere in the subscapularis from unaccustomed eccentric loading, eccentric exercise in an unconditioned muscle, maximal or sub-maximal concentric loading. Placing the muscle in a shortened or lengthened position for an extended period of time can also activate trigger points in the subscapularis. This happens most often when we are sleeping or driving. Activies that can overload your subscapularis include repeated forceful internal rotation. Examples include throwing a baseball, a tennis serve or freestyle swimming. Other activities that can activate subscapularis are involve repeated overhead lifting, such as poorly performed kettle bell swings. Less dramatic movements can also cause activations, such as the sudden overload from reaching to grab a railing on a stairway when you lose balance. Local trauma such as dislocation, joint capsule tears, fractures, or prolonged immobilization of the shoulder in an adducted, internally rotated position can activate and perpetuate trigger points in the related muscles such as subscapularis. Other procedures such as mastectomy, lumpectomy, or radiation treatment can also do this. Once these trigger points have been established they can be perpetuated by slumped posture or other repeated movements that internally rotate your arm.
Myofascial self care always starts with establishing a foundation of diaphragmatic breathing. Once you have taken a few moments get in touch with your breath, we move on to self-compression. Recall that the subscapularis muscle is on the INSIDE of your shoulder blade. This nice lady with the big foam roller might be doing some good, but there is no chance she is going to get underneath her scapula to find that muscle. In fact, as you can see from relative size of the shoulder blade and the tennis ball, that is will be hard to get any type of roller or ball in there. However, if you position yourself carefully, on your side, with your arm extended, you might be able to access a small part of subscapularis in this way. In most cases, you will  have better luck with a knobber of some type that has a smaller head. We like the Back Knobber from Pressure Positive. This type of tool allows you get into the armpit and  into the space behind the shoulder blade. Approach this slowly and gently. If it is too painful you are pushing too hard, or too fast. You may need to experiment with your tool and a body position that faciliates accessing subscapularis. There are a lot of blood vessels and nerves in the armpit, so any self- release should be done with caution. If you feel tingling or circulation changes in your arm you should reposition and take a different approach.
In the end, you may find that you can do it effectively without any self care tools and just using the opposite hand. This video provides and excellent example of manual self release of subscapularis. Most of the muscle is accessible in this position. You can also use this same technique lying on your back if the seated position is uncomfortable. Placing the hand of the affected arm on the opposite shoulder, if possible, gently pulls the shoulder blade forward and improves access. The tenderest spot should be identified and held for 30 seconds until pain subsides. You can repeat the technique up to five times. Massage across the taut bands may also help relieve symptoms. You can also learn to release tightness in the subscapularis by slowly and firmly stretching it using the the middle hand positions in the doorway. It is a little like a doorway stretch to open your chest. However, in this stretch, you are externally rotating your upper arm and stretching the subscapularis. A firm, but gentle and pain-free stretch can be held for 30 seconds and repeated three to five times. You can augment this stretch with a PNF hold-relax technique. Gently push into the door frame with internal rotation to minimally contract the subscapularis muscle for five to ten seconds, followed by relaxation. Then gently stretch the muscle into external rotation by rotating the body away from the doorframe. Another approach is to use your breath to deepen the stretch.  As you inhale, gently push into the doorframe. As you exhale, gently stretch by rotating the body away from the doorframe. You can repeat this sequence three to five times, up to four times per day. Following pressure release or stretching a cold pack may be helpful. If tightness of the posterior capsule develops it is essential that the connective tissue function with the joint be addressed in addition to restoring normal mechanics of your arm and shoulder while treating trigger points in the subscapularis. If treatment is limited to this individual muscle without addressing the mechanics of the entire joint will fail and pain relief will be temporary.
Shoulder pain and limited range of motion are the hallmarks of subscapularis trigger points. Pain is usually concentrated near the back of the shoulder. In addition, pain and tightness often travel down the arm, skipping the elbow and causing pain on the top side of the wrist and forearm. This is analagous to the gluteus minimus referrals that skip the knee and pop up again in the calf. Rotator cuff issues are at least one of the factors in many cases o