Frozen shoulder, or adhesive capsulitis, is a condition that causes restriction of motion in the shoulder joint. The cause of a frozen shoulder is not well understood, but it often occurs for no known reason. Frozen shoulder causes the capsule surrounding the shoulder joint to contract and form scar tissue.

What causes frozen shoulder? Most often, frozen shoulder occurs with no associated injury or discernible cause. There are patients who develop a frozen shoulder after a traumatic injury to the shoulder, but this is not the usual cause.