Whether throwing a ball, paddling a canoe, lifting boxes, or pushing a lawn mower, we rely heavily on our shoulders to perform a number of activities.
Normally, the shoulder has a wide range of motion, making it the most mobile joint in the body. Because of this flexibility, however, it is not very stable and is easily injured.
The shoulder is made up of two main bones: the end of upper arm bone (humerus) and the shoulder blade (scapula). The end of the humerus is round, and it fits into a socket in the scapula. The scapula extends around the shoulder joint to form the roof of the shoulder, and this joins with the collar bone (clavicle). Surrounding the shoulder is a bag of muscles and ligaments. Ligaments connect the bones of the shoulders, and tendons connect the bones to surrounding muscle. Four muscles begin at the scapula and go around the shoulder, where their tendons fuse to form the rotator cuff.
When the shoulder moves, the end of the humerus moves in the socket. Very little of the surface of the bones touch each other. Ligaments and muscles keep the humerus from slipping out of the socket and keep the clavicle attached to the scapula.
To keep shoulders healthy and pain-free, it's important to know how to spot and avoid common injuries.
Shoulder instability occurs when the shoulder feels like it might slip out of place. It occurs most often in young people and athletes. The shoulder becomes unstable when muscles and ligaments that hold it together are stretched beyond their normal limits. For younger people, this condition may be a normal part of growth and development. Shoulders generally stiffen or tighten with age.
In athletes, shoulder instability is caused by activities, such as tackling or pitching that put extreme force on the shoulder. Symptoms of shoulder instability are pain that comes on either suddenly or gradually, a feeling that the shoulder is loose, or a weakness in the arm. Treatment may be rest, physical therapy or surgery.
A shoulder separation, also called a sprain, occurs when the ligaments that hold the clavicle to the roof of the shoulder tear. If this happens, the clavicle is pushed out of place and forms a bump at the top of the shoulder. Sprains are common in falls, when the hand or arm is outstretched to stop the fall, or when the fall is on a hard surface. Symptoms are severe pain when the sprain occurs, a misshapen shoulder and decreased movement of the shoulder. Treatment depends on the severity of the sprain. Ice applied immediately after the injury helps decrease pain and swelling. Keeping the arm in a sling to limit the movement of the shoulder allows ligaments to heal; this is followed by physical therapy exercises. Sometimes, arthroscopic shoulder surgery or another type of surgery is needed.
If the ligaments that hold the shoulder muscles to bones tear and can't hold the joint together, the shoulder is dislocated. A fall onto an outstretched hand, arm or the shoulder itself, or a violent twisting, can cause a shoulder dislocation. The main symptom is pain in the shoulder that becomes worse when the shoulder is moved. Treatment for a dislocation is ice applied immediately after the injury to decrease pain, swelling and bleeding around the joint. Within 15 to 30 minutes of the injury, the joint will be painful and swollen. A dislocated shoulder needs immediate medical care. Doctors treat dislocations by using gentle traction to pull the shoulder back into place. When the shoulder pops out of the socket repeatedly, the condition is called recurrent instability. Recurrent instability can be treated with surgery to repair the torn ligaments.
Rotator Cuff Tear
The rotator cuff is a group of four muscles of the upper arm that raise and rotate the arm. The muscles are attached to the bones by tendons. The job of muscles is to move bones. The tendons of the rotator cuff allow the muscles to move the arm. If the tendons tear, the humerus can't move as easily in the socket, making it difficult to move the arm up or away from the body.
As people age and their physical activity decreases, tendons begin to lose strength. This weakening can lead to a rotator cuff tear. Rotator cuff injuries occasionally occur in younger people, but most of them happen to middle-aged or older adults who already have shoulder problems. This area of the body has a poor supply of blood, making it more difficult for the tendons to repair and maintain themselves. As a person ages, these tendons degenerate. Using your arm overhead puts pressure on the rotator cuff tendons. Repetitive movement or stress to these tendons can lead to impingement, in which the tissue or bone in that area becomes misaligned and rubs or chafes.
The rotator cuff tendons can be injured or torn by trying to lift a very heavy object while the arm is extended, or by trying to catch a heavy falling object.
Symptoms of a torn rotator cuff include tenderness and soreness in the shoulder during an activity that uses the shoulder. A tendon that has ruptured may make it impossible to raise the arm. It may be difficult to sleep lying on that side, and you may feel pain when pressure is put on the shoulder.
Treatment depends on the severity of the injury. If the tear is not complete, your health care provider may recommend RICE, for rest, ice, compression and elevation. Resting the shoulder is probably the most important part of treatment, although after the pain has eased, you should begin physical therapy to regain shoulder movement. Your doctor may prescribe a nonsteroidal anti-inflammatory drug (NSAID) for pain.
This extreme stiffness in the shoulder can occur at any age. It affects approximately 2 percent of Americans, most often between 40 to 60 years of age. Although the causes are not completely understood, it can affect people with diabetes, thyroid disease, heart disease, or Parkinson's disease. It can also occur if the shoulder has been kept immobile for a period of time. It occurs when a minor shoulder injury heals with scar tissue that affects how the joint moves. This scar tissue reduces flexibility in the shoulder and makes it more prone to injury. The major symptom is the inability to move the shoulder in any direction without pain. Treatment can be NSAIDs, cortisone injections or physical therapy. You can reduce further injury and stiffness by stretching before starting activities.
Sudden increases in activity can place extensive stress on the shoulders and lead to a decrease in flexibility. This is a common problem in middle age, especially among "weekend warriors," or people who don't exercise regularly but go out every now and then for an intense sport.
Although painful and inconvenient, these overuse problems can usually be treated with rest, NSAIDs and stretching exercises.
Beginning as early as age 50, some people develop osteoarthritis, which causes painful movement. This occurs as the smooth surfaces of the cartilage that line the bones of the shoulder joint are worn away, and joints begin to wear out and become larger. The most common cause of osteoarthritis is overuse. Treatments for arthritis in the shoulder depend on the severity of pain. The usual treatments are rest, NSAIDs and cortisone injections. In some instances, a replacement of the shoulder joint is necessary.