Tendon calcification in the shoulder joint. X-ray of a shoulder joint showing acute calcification in the subscapularis tendon. The bone on the left is the humerus, the rounded head of which articulates with the scapula on the right. The calcification is the small white area at the base of the articulation of these two bones. Calcification may occur due to damage to the tendon, and can make movement of the joint very painful and stiff (rheumatism). Treatment is by local corticosteroid injection which reduces inflammation, ultrasound application to disrupt the calcium deposit or, occasionally, surgical removal of the deposit.