Frozen shoulder, or adhesive capsulitis, is the development of pain, stiffness, and limited range of motion in the shoulder. The tissues around the joint stiffen, scar tissue forms, and movement of the shoulder becomes difficult and extremely painful. The cause of frozen shoulder is not fully known and there are instances where the cause of a case of frozen shoulder is not identifiable. However, there are some identifiable causes of frozen shoulder.

Frozen shoulder can develop when a person stops using the joint normally due to an injury, pain, or a chronic health condition such as arthritis or diabetes. If there is an extended period where a person is not maintaining full range of motion of the shoulder, frozen shoulder can develop. There are also a number of theories to why frozen shoulder develops. It has been noted to occur more often in women at the same time as menopause. As well, there have been a number of studies that have revealed a genetic component for developing a frozen shoulder as it has been noted that the condition can occur within a family.

There are a number of identifiable risk factors that can increase the risk of frozen shoulder that can include: after injury or surgery (immobility of recovery may cause the shoulder capsule to stiffen), people between the ages of forty to seventy years old (70% of people with frozen shoulder are women), and people with chronic diseases. Also, people with diabetes are two to four times more likely to develop frozen shoulder. Other risk factors include: after suffering a stroke, hyperthyroidism (overactive thyroid), Hypothyroidism (under-active thyroid), Parkinson's disease, and cardiovascular disease (heart disease).

With frozen shoulder, there is a theory that the body develops a rejection reaction as a defense mechanism to the injured shoulder tendons causing the immobility of the shoulder. There have also been studies that have revealed that long-standing round-shouldered posture causes a shortening in one of the shoulder ligaments and this shortening of the ligaments is closely linked to frozen shoulder. When it comes to diagnosis, a symptom is what a patient feels and reports and a sign is something a health professional observes. Signs and symptoms of frozen shoulder include: the shoulder stiffens and then becomes extremely painful with movement so range of motion becomes very limited. Pain typically worsens at night. The shoulder will then become even stiffer which severely limits range of motion to the point it no longer moves.

Doctors will diagnose frozen shoulder based on signs and symptoms and a physical exam. . The severity of frozen can be determined by the doctor when he or she presses and moves certain parts of the shoulder and the arm. Structural problems can be determined with such diagnostic tests as an x-ray or MRI. An arthrogram can also be done which is an X-ray image of the joint taken after a contrast material is injected into it. Signs and symptoms of frozen shoulder develop gradually and can last a couple of years without treatment. Fortunately, there are specialists in the treatment of frozen shoulder.