One of the more common injuries I see is a tear of the upper subscapularis tendon. The subscapularis is a part of the rotator cuff. It is located in the front of the shoulder and is responsible for internally rotating the shoulder. When the subscapularis tendon is injured, the adjacent long head of the bicep tendon can slip into the torn "corner" of the tear. This can lead to weakness and pain in the front of the shoulder.