Calcific tendinitis is a common disorder of the shoulder in which multifocal, cell-mediated calcification in or around a living tendon is usually followed by spontaneous phagocytic resorption. The tendon reconstitutes itself after resorption or surgical removal of the calcium deposit. Although the etiology of calcific tendinitis remains controversial, circumscribed tissue hypoxia and localized tissue pressure may be triggers for the disease process. In some patients with calcific tendinitis, acute or chronic pain is caused by inflammation around the calcium deposits. Mild or moderate chronic pain may be present during the formative, calcium deposition phase, although this phase is latent and asymptomatic in most patients. The acute, resorptive phase may be characterized by an abrupt onset of severe pain that limits function. the pain may be caused by inflammation or secondary to rotator cuff impingement from bursal irritation, thickening, or deposit prominence. Chronic glenohumeral stiffness can also result from calcific tendinitis.