The shoulder is the most movable joint in the body. However, it is an unstable joint because of the range of motion allowed. It is easily subject to injury because the ball of the upper arm is larger than the shoulder socket that holds it. To remain stable, the shoulder must be anchored by its muscles, tendons, and ligaments. Some shoulder problems arise from the disruption of these soft tissues as a result of injury or from overuse or underuse of the shoulder. Other problems arise from a degenerative process in which tissues break down and no longer function well.
Shoulder pain may be localized or may be referred to areas around the shoulder or down the arm. Disease within the body (such as gallbladder, liver, or heart disease, or disease of the cervical spine of the neck) also may generate pain that travels along nerves to the shoulder.
What Are Tendinitis, Bursitis, and Impingement Syndrome of the Shoulder?
These conditions are closely related and may occur alone or in combination. If the rotator cuff and bursa are irritated, inflamed, and swollen, they may become squeezed between the head of the humerus and the acromion. Repeated motion involving the arms, or the aging process involving shoulder motion over many years, may also irritate and wear down the tendons, muscles, and surrounding structures.
Tendinitis is inflammation (redness, soreness, and swelling) of a tendon. In tendinitis of the shoulder, the rotator cuff and/or biceps tendon become inflamed, usually as a result of being pinched by surrounding structures. The injury may vary from mild inflammation to involvement of most of the rotator cuff. When the rotator cuff tendon becomes inflamed and thickened, it may get trapped under the acromion. Squeezing of the rotator cuff is called impingement syndrome.
Tendinitis and impingement syndrome are often accompanied by inflammation of the bursa sacs that protect the shoulder. An inflamed bursa is called bursitis.
Inflammation caused by a disease such as rheumatoid arthritis may cause rotator cuff tendinitis and bursitis. Sports involving overuse of the shoulder and occupations requiring frequent overhead reaching are other potential causes of irritation to the rotator cuff or bursa and may lead to inflammation and impingement.
What Are the Signs of Tendinitis and Bursitis?
Signs of these conditions include:
•the slow onset of discomfort and pain in the upper shoulder or upper third of the arm
•difficulties sleeping on the shoulder
Tendinitis and bursitis also cause pain when the arm is lifted away from the body or overhead. If tendinitis involves the biceps tendon (the tendon located in front of the shoulder that helps bend the elbow and turn the forearm), pain will occur in the front or side of the shoulder and may travel down to the elbow and forearm. Pain may also occur when the arm is forcefully pushed upward overhead.
What Is a Torn Rotator Cuff?
One or more rotator cuff tendons may become inflamed from overuse, aging, a fall on an outstretched hand, or a collision. Sports requiring repeated overhead arm motion or occupations requiring heavy lifting also place a strain on rotator cuff tendons and muscles. Normally, tendons are strong, but a longstanding wearing down process may lead to a tear.
What Are the Signs of a Torn Rotator Cuff?
Typically, a person with a rotator cuff injury feels pain over the deltoid muscle at the top and outer side of the shoulder, especially when the arm is raised or extended out from the side of the body. Motions like those involved in getting dressed can be painful. The shoulder may feel weak, especially when trying to lift the arm into a horizontal position. A person may also feel or hear a click or pop when the shoulder is moved.
How Is a Torn Rotator Cuff Diagnosed?
Pain or weakness on outward or inward rotation of the arm may indicate a tear in a rotator cuff tendon. The patient also feels pain when lowering the arm to the side after the shoulder is moved backward and the arm is raised. A doctor may detect weakness but may not be able to determine from a physical examination where the tear is located.
What Is a Frozen Shoulder?
As the name implies, movement of the shoulder is severely restricted in people with a “frozen shoulder.” This condition, which doctors call adhesive capsulitis, is frequently caused by injury that leads to lack of use due to pain.
Rheumatic disease progression and recent shoulder surgery can also cause frozen shoulder. Intermittent periods of use may cause inflammation. Adhesions (abnormal bands of tissue) grow between the joint surfaces, restricting motion. There is also a lack of synovial fluid, which normally lubricates the gap between the arm bone and socket to help the shoulder joint move. It is this restricted space between the capsule and ball of the humerus that distinguishes adhesive capsulitis from a less complicated painful, stiff shoulder. People at a higher risk for frozen shoulder include those with certain conditions including:
•people who have been in an accident
The condition rarely appears in people under 40 years old.
What Are the Signs of a Frozen Shoulder and How Is It Diagnosed?
With a frozen shoulder, the joint becomes so tight and stiff that it is nearly impossible to carry out simple movements, such as raising the arm. People complain that the stiffness and discomfort worsen at night. A doctor may suspect the patient has a frozen shoulder if a physical examination reveals limited shoulder movement. An arthrogram may confirm the diagnosis.
How Is a Frozen Shoulder Treated?
Treatment of this disorder focuses on restoring joint movement and reducing shoulder pain. Usually, treatment begins with nonsteroidal anti-inflammatory drugs and the application of heat, followed by gentle stretching exercises. These stretching exercises, which may be performed in the home with the help of a therapist, are the treatment of choice.