The Facts about Shoulder Problems

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.

According to the American Academy of Orthopaedic Surgeons, about 4 million people in the United States seek medical care each year for shoulder sprain, strain, dislocation, or other problems. Each year, shoulder problems account for about 1.5 million visits to orthopaedic surgeons - doctors who treat disorders of the bones, muscles, and related structures.

Structures and Function of the Shoulder
The shoulder joint is composed of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone). Two joints facilitate shoulder movement. The acromioclavicular (AC) joint is located between the acromion (part of the scapula that forms the highest point of the shoulder) and the clavicle. The glenohumeral joint, commonly called the shoulder joint, is a ball-and-socket type joint that helps move the shoulder forward and backward and allows the arm to rotate in a circular fashion or hinge out and up away from the body. (The "ball" is the top, rounded portion of the upper arm bone or humerus; the "socket," or glenoid, is a dish-shaped part of the outer edge of the scapula into which the ball fits.) The capsule is a soft tissue envelope that encircles the glenohumeral joint. It is lined by a thin, smooth synovial membrane.

The bones of the shoulder are held in place by muscles, tendons, and ligaments. Tendons are tough cords of tissue that attach the shoulder muscles to bone and assist the muscles in moving the shoulder. Ligaments attach shoulder bones to each other, providing stability.

The rotator cuff is a structure composed of tendons that, with associated muscles, holds the ball at the top of the humerus in the glenoid socket and provides mobility and strength to the shoulder joint.

Two filmy sac-like structures called bursae permit smooth gliding between bone, muscle, and tendon. They cushion and protect the rotator cuff from the bony arch of the acromion.

Shoulder Dislocation
The shoulder joint is the most frequently dislocated major joint of the body. In a typical case of a dislocated shoulder, a strong force that pulls the shoulder outward or extreme rotation of the joint pops the ball of the humerus out of the shoulder socket. Dislocation commonly occurs when there is a backward pull on the arm that either catches the muscles unprepared to resist or overwhelms the muscles. When a shoulder dislocates frequently, the condition is referred to as shoulder instability. A partial dislocation where the upper arm bone is partially in and partially out of the socket is called a subluxation.

Signs and Diagnosis
The shoulder can dislocate either forward, backward, or downward. Not only does the arm appear out of position when the shoulder dislocates, but the dislocation also produces pain. Muscle spasms may increase the intensity of pain. Swelling, numbness, weakness, and bruising are likely to develop. Problems seen with a dislocated shoulder are tearing of the ligaments or tendons reinforcing the joint capsule and, less commonly, nerve damage. Doctors usually diagnose a dislocation by a physical examination, and X-rays may be taken to confirm the diagnosis and to rule out a related fracture.

Treatment
Doctors treat a dislocation by putting the ball of the humerus back into the joint socket - a procedure called a reduction. The arm is then immobilized in a sling or a device called a shoulder immobilizer for several weeks. Usually the doctor recommends resting the shoulder and applying ice three or four times a day. After pain and swelling have been controlled, the patient enters a rehabilitation program that includes exercises to restore the range of motion of the shoulder and strengthen the muscles to prevent future dislocations. These exercises may progress from simple motion to the use of weights.

Shoulder Separation
A shoulder separation occurs where the collarbone (clavicle) meets the shoulder blade (scapula). When ligaments that hold the joint together are partially or completely torn, the outer end of the clavicle may slip out of place, preventing it from properly meeting the scapula. Most often the injury is caused by a blow to the shoulder or by falling on an outstretched hand.

Signs and Diagnosis
Shoulder pain or tenderness and, occasionally, a bump in the middle of the top of the shoulder (over the AC joint) are signs that a separation may have occurred. Sometimes the severity of a separation can be detected by taking X-rays while the patient holds a light weight that pulls on the muscles, making a separation more pronounced.

Treatment
A shoulder separation is usually treated conservatively by rest and wearing a sling. Soon after injury, an ice bag may be applied to relieve pain and swelling. After a period of rest, a therapist helps the patient perform exercises that put the shoulder through its range of motion. Most shoulder separations heal within 2 or 3 months without further intervention. However, if ligaments are severely torn, surgical repair may be required to hold the clavicle in place.

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.

Signs and Diagnosis
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.

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. X-rays, if taken, may appear normal. An MRI can help detect a full tendon tear, but does not detect partial tears.

Treatment
Doctors usually recommend that patients with a rotator cuff injury rest the shoulder, apply heat or cold to the sore area, and take medicine to relieve pain and inflammation. Other treatments might be added, such as electrical stimulation of muscles and nerves, ultrasound, or a cortisone injection near the inflamed area of the rotator cuff. The patient may need to wear a sling for a few days. If surgery is not an immediate consideration, exercises are added to the treatment program to build flexibility and strength and restore the shoulder's function. If there is no improvement with these conservative treatments and functional impairment persists, the doctor may perform arthroscopic or open surgical repair of the torn rotator cuff.

Frozen Shoulder (Adhesive Capsulitis)
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 with diabetes, stroke, lung disease, rheumatoid arthritis, and heart disease, or who have been in an accident, are at a higher risk for frozen shoulder. The condition rarely appears in people under 40 years old.

Signs and Diagnosis
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.

Treatment
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. In some cases, transcutaneous electrical nerve stimulation (TENS) with a small battery-operated unit may be used to reduce pain by blocking nerve impulses. If these measures are unsuccessful, the doctor may recommend manipulation of the shoulder under general anesthesia. Surgery to cut the adhesions is only necessary in some cases.

Shoulder Fracture
A fracture involves a partial or total crack through a bone. The break in a bone usually occurs as a result of an impact injury, such as a fall or blow to the shoulder. A fracture usually involves the clavicle or the neck (area below the ball) of the humerus.

Signs and Diagnosis
A shoulder fracture that occurs after a major injury is usually accompanied by severe pain. Within a short time, there may be redness and bruising around the area. Sometimes a fracture is obvious because the bones appear out of position. Both diagnosis and severity can be confirmed by X-rays.

Treatment
When a fracture occurs, the doctor tries to bring the bones into a position that will promote healing and restore arm movement. If the clavicle is fractured, the patient must at first wear a strap and sling around the chest to keep the clavicle in place. After removing the strap and sling, the doctor will prescribe exercises to strengthen the shoulder and restore movement. Surgery is occasionally needed for certain clavicle fractures.

Fracture of the neck of the humerus is usually treated with a sling or shoulder immobilizer. If the bones are out of position, surgery may be necessary to reset them. Exercises are also part of restoring shoulder strength and motion.

Self-Care
If you receive a shoulder injury, remember RICE: Rest, Ice, Compression, and Elevation.

• Rest: Reduce or stop using the injured area for 48 hours.
• Ice: Put an ice pack on the injured area for 20 minutes at a time, 4 to 8 times per day. Use a cold pack, ice bag, or a plastic bag filled with crushed ice that has been wrapped in a towel.
• Compression: Compression may help reduce the swelling. Compress the area with bandages, such as an elastic wrap, to help stabilize the shoulder.
• Elevation: Keep the injured area elevated above the level of the heart. Use a pillow to help elevate the injury.

If pain and stiffness persist, see a doctor.

The information in this article has been made available by the National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health.

Each year, Medical College of Wisconsin physicians care for more than 180,000 patients, representing nearly 500,000 patient visits. Medical College physicians practice at Children's Hospital of Wisconsin, Froedtert Memorial Lutheran Hospital, the Milwaukee VA Medical Center, and many other hospitals and clinics in Milwaukee and southeastern Wisconsin.