The subscapularis tendon sits at the front of the shoulder and is the largest of four tendons that together are known as the rotator cuff. Its role is to turn the arm inwards and behind the back and it is important when doing any lifting movements across your chest, as in putting on a scarf. It is essential for overhead sports, such as swimming, racquet sports and throwing.
The upper part of the tendon can be involved in impingement syndrome. Pain may be felt at shoulder height when lifting the arm away from the body with the palm facing upwards at the front of the shoulder or when turning the bent arm away from the body to its full extent. Movements involving lifting the arm up and across the body may also produce a nipping pain at shoulder height.
Physiotherapy can help with treatment including a specific massage technique to the painful area, called frictions, and mobilisations. Electrotherapy may be used, particularly ultrasound. Activities that aggravate the pain should be avoided initially but exercises will be given that improve the strength of the subscapularis muscle and tendon and help to stabilise the shoulder. Advice will also given on posture to help to prevent recurrence. In cases that don’t respond to this conservative management, an injection may be given, usually into the subacromial bursa that blends with the tendon rather than directly into the tendon itself.
Partial or complete tears of the subscapularis tendon are more rare than in the other rotator cuff tendons but when they do occur, weakness will be noticed when trying to lift the arm across the body or when pressing the arm into the ‘belly’ at waist height with the elbow bent. A surgical opinion will be appropriate if rupture is suspected.