Before getting directly into subscapularis tear, let’s first understand the function of subscapularis muscle in the shoulder.
Do you know why we can internally rotate the shoulder effortlessly? If not, here it is, it is because of subscapularis muscle in our shoulder. To explain it further, when your arm is internally rotated, your palm is facing back, behind your body. You may be aware of rotator cuff, a group of muscles that attaches your upper arm to the shoulder, the subscapularis is the largest muscle in the rotator cuff. You can lift and rotate your arm because of the assistance of subscapularis muscle. Subscapularis connects shoulder blade to the humerus. In fact, subscapularis is the largest & strongest cuff muscle, providing 53% of total cuff strength. Subscapularis muscle plays a pivotal role in overhead sports, such as swimming, racquet sports and throwing.
However, rotator cuff muscles are prone to tear owing to overuse, trauma or age-related conditions and subscapularis muscle is not an exception. Though tears of the subscapularis tendon are less common compared to supraspinatus and infraspinatus tendon tears, they can be much more painful, since the restraints to the long head of biceps tendon are often also torn and the biceps tendon dislocates from its groove. The biceps tendon then also becomes painful and weak. The severity of the tear can range from mild to tearing up the whole muscle. Treatment is given based on the size of the tear. Subscapularis tears are generally seen near the end of the tendon that connects to the humerus. It can also lead to issues with biceps muscle.