What most people call the shoulder is really several joints that combine with tendons and muscles to allow a wide range of motion in the arm — from scratching your back to throwing the perfect pitch.
Mobility has its price, however. It may lead to increasing problems with instability or impingement of the soft tissue or bony structures in your shoulder, resulting in pain. You may feel pain only when you move your shoulder, or all of the time. The pain may be temporary or it may continue and require medical diagnosis and treatment.
This article explains some of the common causes of shoulder pain, as well as some general treatment options. Dr van den Berg can give you more detailed information about your shoulder pain.
The shoulder is a ball-and-socket type joint made up of three bones:
The head of the humerus fits into a socket (called the “Glenoid”) in the shoulder blade. A group of muscles and tendons keeps the shoulder centred in the shoulder socket. These muscles are called the rotator cuff. They cover the head of humerus and attach it to your scapula. There is a lubricating sac called a bursa between the rotator cuff and the bone on top of your shoulder (acromion). This bursa allows the rotator cuff tendons to move freely when you move your arm in all directions.
The biceps muscle (in front of your upper arm) helps you bend your elbow and rotate your forearm. It also stabilizes the shoulder. The biceps muscle has two tendons that attach it to bones in the shoulder.
The Glenoid (socket) is lined with soft cartilage structure called the labrum. This tissue helps to stabilize the head of the humerus into the shoulder socket.
Most shoulder problems fall into four major categories:
Bursae are small, fluid-filled sacs that are located in joints throughout the body, including the shoulder. They act as cushions between bones and the overlying soft tissues, and help reduce friction between the gliding muscles and the bone.
Sometimes, excessive use of the shoulder leads to inflammation and swelling of the bursa between the rotator cuff and part of the shoulder blade known as the acromion. The result is a condition known as subacromial bursitis. Bursitis often occurs in association with rotator cuff tendinitis. The many tissues in the shoulder can become inflamed and painful. Many daily activities, such as combing your hair or getting dressed, may become difficult.
A tendon is a cord that connects muscle to bone. Most tendinitis is a result of a wearing down of the tendon that occurs slowly over time, much like the wearing process on the sole of a shoe that eventually splits from overuse.
Generally, tendinitis is one of two types:
The most commonly affected tendons in the shoulder are the four rotator cuff tendons and one of the biceps tendons. The rotator cuff is made up of four small muscles and their tendons that cover the head of your humerus and keep it in the shoulder socket. Your rotator cuff helps provide shoulder motion and stability.
Splitting and tearing of tendons may result from acute injury or degenerative changes in the tendons due to advancing age, long-term overuse and wear and tear, or a sudden injury. These tears may be partial or may completely split the tendon into two pieces. In most cases of complete tears, the tendon is pulled away from its attachment to the bone. Rotator cuff and biceps tendon injuries are among the most common of these injuries.
Shoulder impingement occurs when the top of the shoulder blade (acromion) puts pressure on the underlying soft tissues (bursa and rotator cuff) when the arm is lifted away from the body. As the arm is lifted, the acromion rubs (“impinges”) on, the rotator cuff tendons and bursa. This can lead to bursitis and tendinitis, causing pain and limiting movement. Over time, severe impingement can even lead to a rotator cuff tear.
Shoulder instability occurs when the head of the humerus is forced out of the shoulder socket (glenoid). This can happen as a result of a sudden injury or from overuse. Shoulder dislocations can be partial, with the ball of the humerus coming just partially out of the socket (called a subluxation). A complete dislocation means the ball comes all the way out of the socket.
Once the ligaments, tendons, and muscles around the shoulder become loose or torn, dislocations can occur repeatedly. Recurring dislocations, which may be partial or complete, cause pain and unsteadiness when you raise your arm or move it away from your body. Repeated episodes of subluxations or dislocations lead to an increased risk of developing arthritis in the joint.
Shoulder pain can also result from arthritis. There are many types of arthritis. The most common type of arthritis in the shoulder is osteoarthritis, also known as "wear and tear" arthritis. Symptoms, such as swelling, pain, and stiffness, typically begin during middle age. Osteoarthritis develops slowly and the pain it causes worsens over time.
Osteoarthritis may be related to sports or work injuries and chronic wear and tear. Other types of arthritis can be related to rotator cuff tears, infection, or an inflammation of the joint lining.
Often people will avoid shoulder movements in an attempt to lessen arthritis pain. This sometimes leads to a tightening or stiffening of the soft tissue parts of the joint, resulting in a painful restriction of motion.
Shoulder fractures commonly involve the clavicle (collarbone), humerus (upper arm bone), and scapula (shoulder blade). Shoulder fractures in older patients are often the result of a fall from standing height. In younger patients, shoulder fractures are often caused by a high energy injury, such as a motor vehicle accident or contact sports injury. Fractures often cause severe pain, swelling, and bruising about the shoulder.
In the case of an acute injury causing intense pain, seek medical care as soon as possible. If the pain is less severe, it may be safe to rest a few days to see if time will resolve the problem. If symptoms persist, see a doctor.
Your doctor will conduct a thorough evaluation in order to determine the cause of your shoulder pain and provide you with treatment options.
The first step in the evaluation is a thorough medical history. Your doctor may ask how and when the pain started, whether it has occurred before and how it was treated, and other questions to help determine both your general health and the possible causes of your shoulder problem. Because most shoulder conditions are aggravated by specific activities, and relieved by specific activities, a medical history can be a valuable tool in finding the source of your pain.
A comprehensive examination will be required to find the causes of your shoulder pain. Your doctor will look for physical abnormalities, swelling, deformity or muscle weakness, and check for tender areas. He or she will observe your shoulder range of motion and strength.
Your doctor may order specific tests to help identify the cause of your pain and any other problems.