This condition develops as a result of calcium depositition within the substance of the rotator cuff tendons. The supraspinatus tendon is most frequently affected.
The subacromial area lies between the top of the arm bone (humerus) and a bony prominence on the shoulder blade (acromion). The coracoacromial ligament completes the arch.
The patient, who is usually young or middle aged, presents with sudden onset excruciating pain in the shoulder.
A calcific deposit (Calcifying tendonitis) is found in the tendons and this itself may be the cause of the symptoms. It is usually associated with some degree of impingement.
Fig: Calcific deposit in the Rotator cuff tendon