Shoulders

Shoulder Anatomy

An inside look at the structure of the shoulder.

The shoulder is made up of three bones: the scapula (shoulder blade), clavicle (collarbone) and humerus (upper arm bone). Two joints in the shoulder allow it to move: the acromioclavicular joint, where the highest point of the scapula (acromion) meets the clavicle, and the glenohumeral joint.

The glenohumeral joint is the one most people think of as the shoulder joint. It is formed where a ball (head) at the top of the humerus fits into a shallow cuplike socket (glenoid) in the scapula, allowing a wide range of movement. The surfaces of the bones where the ball and socket meet are covered with smooth, elastic cartilage that absorbs shock and allows the joint to move easily.

Because the socket of the shoulder is shallow, the joint relies on surrounding soft tissues to support it and hold the components in place. Many of these soft tissues surround the joint to form a protective capsule, which is lined with a thin membrane called the synovium. The synovium produces a fluid (synovial fluid) to cushion and lubricate the joint.

Other key structures of the shoulder include:

• labrum, a fibrous ring of cartilage that surrounds the glenoid, or shoulder socket, to create a deeper socket for the ball to stabilize the joint
• rotator cuff, a network of muscles and tendons that cover the top of the humerus, or upper arm bone, to hold it place and enable the arm to rotate 
• deltoid, the largest and strongest muscle of the shoulder, the deltoid muscle provides the strength to lift the arm.
• biceps tendon, originating at the top of the shoulder socket, this tendon attaches to the biceps muscle, which allows the elbow to bend and the forearm to rotate.

Shoulder Pain Causes

Arthritis & Diseases that Affect the Shoulder

Joint inflammation and other problems that may be to blame for shoulder pain

Many forms of arthritis and related conditions that affect the joints, muscles and/or bones can cause problems like pain, stiffness and swelling in the shoulders. Here are some diseases that can affect the shoulders.

• Osteoarthritis. The most common form of arthritis, osteoarthritis is a chronic condition characterized by the breakdown of the cartilage that cushions the ends of the bones where they meet to form joints. This breakdown causes the bones to rub against each other, causing stiffness, pain and loss of movement in the joint. Bony projections, or spurs, can develop around the joint. In the shoulder, osteoarthritis often occurs after an injury.

• Rheumatoid arthritis. Rheumatoid arthritis is a chronic inflammatory disease of the joints that occurs when the body’s immune system – which normally protects us from infection – mistakenly attacks the synovium, the thin membrane that lines the joints. The result can be joint damage, pain, swelling, inflammation, loss of function and disability. The joint involvement of rheumatoid arthritis is symmetrical. That means if one shoulder is affected the other likely will be too.

• Juvenile arthritis. Juvenile arthritis is the term used to describe arthritis when it begins before age 16. There are several different types of juvenile arthritis that can cause pain, swelling and potentially destruction of the shoulders.

• Gout. Gout is a form of arthritis that occurs when excess uric acid, a bodily waste product circulating in the bloodstream, is deposited as needle-shaped monosodium urate crystals in tissues of the body, including the joints. For many people, the first symptom of gout is excruciating pain and swelling in the big toe – often following a trauma, such as an illness or injury. Subsequent attacks may occur off and on in other joints, typically the feet, ankles, hands, wrists, elbows and knees. Shoulder involvement is less common, but can occur.

• Calcium pyrophosphate dihydrate crystal deposition disease (pseudogout). Like gout, pseudogout occurs when crystals form within the joints. With pseudogout, however, the crystals are formed from a salt called calcium pyrophosphate dihydrate. Although pseudogout occurs mostly in older people, it can affect younger people, particularly if they have other health problems. And like gout, pseudogout can cause intense pain and swelling, which often comes during the night. Pseudogout most commonly affects the knee, wrist and shoulder joints.

• Reactive arthritis. Reactive arthritis is a chronic form of arthritis that often occurs following an infection of the genital, urinary or gastrointestinal system. Features of reactive arthritis include inflammation and swelling of the joints, eyes and structures within the gastrointestinal or genitourinary tracts, such as intestines, kidneys or bladder. Although the ankles, knees and joints of the feet often are the first joints affected by reactive arthritis, it also can affect the shoulder.

• Lupus. Lupus is a chronic autoimmune disease, meaning the body's immune system creates antibodies that attack healthy tissues, including the joints, skin, heart, lungs, and kidneys. The joints farthest from the body, such as those of the hands and feet, are most commonly affected by lupus; however, muscle inflammation that often accompanies lupus usually affects the shoulders as well as the muscles of the neck, pelvis, thighs and upper arms.

• Infectious arthritis. Also called septic arthritis, infectious arthritis refers to arthritis that is caused by an infection within the joint. Infectious arthritis is often caused by bacteria that spread through the bloodstream to the joint. Sometimes it is caused by viruses or fungi. Infectious arthritis can affect the shoulders. Untreated, infection can lead to joint destruction.

• Polymyositis. Polymyositis, meaning inflammation of many muscles, is one of a group of disorders characterized by inflammation and muscle weakness. The main symptom of polymyositis is symmetric weakness of the large muscles closest to the trunk. Initially, the hips, thighs and shoulders are commonly affected. The shoulder and pelvic girdle muscles are most severely affected. The weakness may make it difficult to lift heavy objects or even lift your arm to comb your hair or to put on a coat.

• Dermatomyositis. Dermatomyositis is an inflammatory disease of the muscles, like polymyositis. However, dermatomyositis has a somewhat severe onset and affects both children and adults. In addition to the symptoms of polymyositis, including pain and weakness of the muscles around the shoulders and pelvis, symptoms of dermatomyositis also include a patchy skin rash, purplish discoloration of the eyelids, swelling around the eyes, changes around the nail beds and calcium deposits in the shoulders, pelvis, hips, calves and thighs, which may limit motion.

• Polymyalgia rheumatica. Polymyalgia rheumatica is a rheumatic disorder characterized by pain and stiffness in the neck, shoulders and hips. It usually develops gradually but may come on suddenly. It is rare in people less than age 50, but becomes more common with age. It often resolves on its own over time.

• Osteonecrosis. Also called avascular necrosis, aseptic necrosis or ischemic necrosis, osteonecrosis is a disease in which a temporary or permanent loss of blood supply to the bone causes the bone to die and eventually collapse. It often occurs in a bone near the joint, which causes the collapse of the joint surface. The disease is most common in the top of the thigh bone (femur). Other common sites include the upper arms, knees, shoulders and ankles.

• Lyme disease. Lyme disease is an infectious disease spread by the bite of deer ticks infected with the bacteria Borrelia burgdorferi. The first symptoms are often a bulls-eye-shaped rash and flu-like symptoms. If not treated early, the disease symptoms may progress to involvement of the heart, nervous system and joints, including the shoulder.

• Other diseases. Sometimes pain in the shoulders is due to causes outside the joint. Causes of pain to the shoulder are as diverse as gallstones, liver abscess, angina or heart attack, or even an ectopic pregnancy. If you experience unusual shoulder pain it is important to see a doctor to find the cause.

Shoulder Injuries

Learn about some common and some not-so-common shoulder injuries.

The shoulder is the most movable joint of the body. It also is one of the most unstable joints. As a result, it is the site of many problems and injuries. The following are some of the most common shoulder injuries:

• Dislocated shoulder. The shoulder is one of the most frequently dislocated joints. Pulling the shoulder backward or rotating it too far can cause the ball of the upper arm bone (humerus) to pop out of the socket (glenoid). Shoulder instability is a condition in which the shoulder dislocates frequently. Sometimes the ball of the upper arm bone is only partially out of the socket. This is called a partial location or subluxation.

• Shoulder separation. This injury involves the acromioclavicular (AC) joint, where the collarbone meets the shoulder blade (scapula). The injury occurs when a fall, blow to the shoulder or other trauma tears the ligaments that hold the AC joint together. The outer end of the collarbone may slip out of place, resulting in shoulder pain – ranging from mild to severe – and possibly a bump on the top of the shoulder.

• Glenoid labrum tear. Also called shoulder joint tear, this is an injury to the cartilage that surrounds the rim of the shoulder socket. This injury often results from repetitive motion or trauma from a fall, pull or blow to the shoulder. Symptoms include pain, loss of strength, decreased range of motion and catching, locking or popping of the shoulder.

• Torn rotator cuff. Overuse, aging, a fall or other type of trauma can strain the rotator cuff tendons, which can cause them to become inflamed, leading to a tear. The rotator cuff is a network of muscles and tendons that cover the top of the upper arm bone (humerus) to hold it place and enable the arm to rotate. If you experience a rotator cuff injury you may experience pain over the deltoid muscle at the top and outer side of the shoulder, especially when you raise or extend your arm out from your body. Your shoulder may feel weak and you may hear a click or pop when you try to move your shoulder.

• Frozen shoulder. Also called adhesive capsulitis, frozen shoulder is a condition in which the shoulder's movement is severely restricted due to the growth of abnormal bands of tissue (called adhesions) between joint surfaces and a lack of synovial fluid to lubricate the joint. Frozen shoulder may have several different causes, including an injury that forces you to stop using your shoulder due to pain, arthritis or recent surgery.

• Shoulder fracture. A shoulder fracture is a brake or crack in one of the bones of the shoulder, which usually occurs from a fall or blow. The most commonly fractured areas in the shoulder are the collarbone, or clavicle, and the top of the upper arm bone, or humerus, just below the ball. A shoulder fracture usually causes severe pain, with redness and bruising.

• Impingement syndrome. This condition is a form of tendinitis in which an inflamed and thickened rotator cuff gets squeezed by or impinged on by the acromion, or edge of the shoulder blade, when the arm is moved. Impingement is one of the most common causes of shoulder pain.

• Shoulder bursitis. Bursitis is inflammation of bursae (singular: bursa) small, fluid-filled sacs that cushion and lubricate large joints, such as the knees, hips and shoulders. Bursitis in the shoulder can have a number of causes including an injury or underlying form of arthritis or rheumatic disease. The result can be pain, swelling and tenderness in the affected area, particularly with motion.

Shoulder Pain Diagnosis

Diagnosing Shoulder Problems

Tests your doctor uses to find the cause of shoulder pain.

Diagnosing a shoulder problem will begin with a physical exam and assessment of your medical history. During the medical history your doctor will ask you questions such as:

• What symptoms are you experiencing?
• When did you first start noticing them? Were they the result of an injury?
• Are your symptoms worse after activity or rest? Are there certain activities that make them worse – or better?
• Do you recall having an illness or accident around the time your symptoms began?
• Are you experiencing symptoms in any joints besides the shoulder(s)?
• Do any of your family members have arthritis or other shoulder problems?
• Do you have other medical problems that could be causing your symptoms?

During the physical exam your doctor will look at and touch your shoulders and any other joints you may be experiencing problems with. Your doctor will be looking for areas that have tenderness, pain or swelling, as well as indications that the joint may be damaged.  Depending on the findings of the history and exam, your doctor may order lab tests and imaging tests to help make or confirm a diagnosis.

Imaging Tests

Noninvasive tests that help your doctor see inside your shoulders.

Imaging tests can allow your doctor to see the structures inside your shoulders. The most common imaging tests to diagnose shoulder problems are:

X-ray (radiography). A standard X-ray is a simple test in which an X-ray beam (a form of electromagnetic radiation) is passed through the shoulder to create a two-dimensional picture of the bones that form the joint. Your doctor can use X-rays to view:

• joint space. Narrowing of the space between the bones, which are normally covered by cartilage, can be a sign of arthritis and its severity.
• bone spurs. Bony overgrowths at the joint are a sign of osteoarthritis.
• fractures. Broken bones will show up on X-rays, however, small cracks in the bone may not.

In some cases a contrast dye is injected into the shoulder to enable the doctor to better see the joint on X-ray. This is called arthrography.

• Computerized axial tomography (CAT) scan. Also called a computed tomography (or CT) scan, this noninvasive test combines X-ray equipment with sophisticated computers to produce multiple images, which are combined to depict cross-sectional slices of internal structures. CT scans may be used to diagnose shoulder fractures that don't show up on X-ray. They also show soft tissues, such as cartilage, ligaments and muscles, more clearly than traditional X-rays, so they are more useful for diagnosing certain shoulder problems, including arthritis and soft tissue injuries.
  
• Magnetic resonance imaging (MRI). This procedure uses a strong magnet linked to a computer to create a picture of the internal structures in black and white and shades of gray. Because an MRI shows the soft tissues, as well as the bones, it is particularly useful for diagnosing injuries to the cartilage, tendons and ligaments, as well as areas of swelling.
  
• Bone scan. This technique can be used to view stress fractures caused by repetitive trauma. It involves injecting a small amount of radioactive material into the bloodstream. The material collects in the bones, particularly areas of new bone growth where fractures are healing, enabling doctors to see those areas with a scanner.

Lab Tests for Shoulder Problems

Tests that tell what's going on inside your body.

Often a sample of blood or joint fluid can help you doctor confirm a diagnosis. For example, a blood test showing high blood levels of rheumatoid factor – an antibody that acts against the blood component gamma globulin – or an antibody called anti-cyclic citrullinated peptide antibody (anti-CCP) may suggest rheumatoid arthritis. High levels of antinuclear antibodies (ANAs), abnormal antibodies directed against the cells' nuclei, could suggest lupus or another inflammatory disease. A high erythrocyte sediment rate (ESR, or sed rate), along with muscle pain in the shoulders, could help confirm a diagnosis of polymyositis or polymyalgia rheumatica.

Tests of fluid drawn with a needle from the joint may reveal crystals of uric acid, confirming a diagnosis of gout; calcium pyrophosphate dehydrate, confirming pseudogout; or a bacterium, suggesting that joint inflammation is caused by an infection.

If your doctor suspects your pain may be caused by disease of the heart, liver, gallbladder or other organ or area of the body, different types of blood tests may aid in the diagnosis of those problems.

Shoulder Pain Treatment

Medications to Treat Shoulders

What you need to know about the many medications used for shoulder problems.

Medications to ease pain, relieve inflammation, slow bone loss, modify the course of an inflammatory disease or prevent joint damage are an important part of treatment for many shoulder problems. The medications used to treat arthritis and other problems that affect the shoulders will depend largely on the form of arthritis or related condition you have. The types of medications commonly used in arthritis treatment are:

• Nonsteroidal anti-inflammatory drugs. Including more than a dozen different drugs, some of which are available without a prescription, nonsteroidal anti-inflammatory drugs (NSAIDs) are used to help ease arthritis pain and inflammation. They are used for all forms of arthritis.

• Corticosteroids. These quick-acting drugs, similar to the cortisone made by your own body, are used to control inflammation. If inflammation is due to a systemic inflammatory disease, your doctor may prescribe oral corticosteroids. If inflammation is limited to one or a few joints, your doctor may inject a corticosteroid preparation directly into the joint.

• Analgesics. Analgesics are among the most commonly prescribed drugs for many forms of arthritis. They also may be used to relieve pain from fractures and other injuries. Unlike NSAIDs, which target both pain and inflammation, analgesics are designed purely for pain relief. For that reason, they may be safe for people who are unable to take NSAIDs due to allergies or stomach problems, for example. When used as prescribed, they’re also an appropriate, and possibly safer, choice for people whose arthritis causes pain but not inflammation.

If pain is in the soft tissues, you may find relief from an analgesic salve, rub or balm available over the counter under trade names such as Aspercreme, Ben-Gay, Capzasin-P, Eucalyptamint, Icy Hot, Voltaren Gel and Zostrix.  These topical preparations work through a variety of active ingredients and may be helpful if you are unable to take oral medications or if your medications fail to relieve pain or reduce it to a manageable level.

• Disease modifying anti-rheumatic drugs. Disease-modifying anti-rheumatic drugs (DMARDs) are drugs that work slowly to modify the course of inflammatory disease. Different DMARDs may be useful for a number of different forms of arthritis, including rheumatoid arthritis, which can affect the shoulders.

• Gout medications. Some medications for gout are designed to reduce levels of uric acid in the blood to prevent future attacks of joint pain and inflammation. Others are designed to relieve the pain and inflammation of an acute attack. Many people with gout take both types of medication.

• Biologic response modifiers. The newest category of medications used for rheumatoid arthritis and a few other inflammatory forms of arthritis are the biologic agents. There are currently eight such agents approved by the FDA. Each blocks a step in the inflammation process without suppressing the entire immune system.

• Osteoporosis medications. Osteoporosis medications are those used to slow the loss of bone or help the body build new bone. Although they are not used specifically to treat shoulders, strong bones are less prone to fracture. Osteoporosis is the main cause of shoulder fractures in older people.

Shoulder Surgery

Shoulder replacement, fracture repair and other surgeries for shoulders.

If a shoulder is injured or arthritis interferes with function and causes pain that can't be controlled with medication, surgery may be an option – or a necessity. Here are some of the most commonly performed shoulder surgeries.

• Fracture repair. While many fractures can be healed by immobilizing the shoulder with tape or a sling, other fractures require surgery to position the bone and, in some cases, hardware is used to hold the pieces of bone in place while they heal. The procedure will depend on which bone(s) has been fractured and how badly.
  
• Shoulder replacement. For arthritis of the shoulder that is not helped by nonoperative treatments, shoulder replacement surgery may be needed to relieve pain and restore mobility. Pain relief is the main reason for having a shoulder replacement.

There are different types of shoulder replacement. Conventional shoulder replacement surgery involves replacing the damaged ball-and-socket joint with a plastic socket and a metal ball attached to a stem inserted in the upper arm bone, or humerus. In some cases, the surgeon replaces just the ball and leaves the natural socket.

Another type of shoulder replacement, called reverse shoulder replacement, is a better option for people who have torn rotator cuffs or have had a previous should replacement that failed. This procedure is similar to conventional shoulder replacement surgery, and also involves replacing the ball and socket. However, unlike the conventional procedure, the ball is attached to the shoulder bone and the socket is attached to the upper arm bone, or humerus, in reverse shoulder replacement. This makes it possible for the deltoid muscle, instead to the torn rotator cuff, to life the arm.

• Arthroscopy. Arthroscopy is a procedure that uses a lighted scope and small surgical instruments to diagnose and repair joint problems through several small incisions instead of opening the entire joint.

The shoulder is one of the most frequently examined joints using arthroscopy. Surgeons can use arthroscopy to diagnose or evaluate rotator cuff tendon tears, impingement syndrome and recurrent dislocations.

Surgeons may also use arthroscopic surgery to repair rotator cuff injuries, remove inflamed synovium tissue in the shoulder or remove loose bone or cartilage.

Learn more about Arthroscopic surgery from the American Academy of Orthopaedic Surgeons.

Shoulder Pain Care

Ways to Prevent Pain and Maintain Daily Activities

Techniques and devices that can help you live better with shoulder pain.

Many shoulder injuries can be treated at home with over-the-counter (OTC) nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin IB) and naproxen (Aleve). If you cannot tolerate NSAIDs, or you already are taking anti-inflammatory drugs for arthritis, contact your doctor before taking an OTC pain-reliever.

Within 48 hours of the injury, you should also begin self-care measures. Use the acronym RICE to help remember these treatments:

• Rest. Take a break from activity. Avoid using your injured shoulder ankle.
• Ice. Place an ice pack on your shoulder for 15 to 20 minutes at a time to reduce pain and swelling.
• Compression. Compress the shoulder with an elastic bandage to help stabilize the shoulder and reduce swelling.
• Elevation. As much as possible, keep your shoulder elevated higher than your heart. Use pillows to prop up your shoulder when you lie down.

Whether you have an acute injury or chronic arthritis, medications don't always relieve pain completely. At times when you need extra help with pain relief, recovery or help with daily activities, here are some techniques and devices worth trying.

Hot and cold. While cold is helpful for reducing inflammation from a new shoulder injury, it also can be helpful for chronic pain or for the pain and inflammation of an arthritis flare. For aching shoulders without acute inflammation, heat may provide relief.

Physical therapy. In the early stages of arthritis, physical therapy may be helpful for strengthening the shoulder muscles and maintaining joint range of motion. Your doctor may also prescribe physical therapy for some shoulder injuries or to help in recovering from shoulder surgery.

To locate a physical therapist, check out the American Physical Therapy Association.

Transcutaneous electrical nerve stimulation (TENS). A technique in which a weak electric current is administered through electrodes placed on the skin, TENS is believed to stop messages from pain receptors from reaching the brain. It may be useful for short-term pain control in some people with shoulder arthritis.

Slings. For certain shoulder fractures, including most fractures of the scapula, nonsurgical treatment using a sling to immobilize the joint is an effective treatment. The shoulder may be stiff when your doctor first removes the sling. An exercise or physical therapy program will be necessary to regain full motion of the shoulder after immobilization.

Read more about treatment for shoulder blade fractures from the American Academy of Orthopaedic Surgeons.

Electrical stimulation. Electrical stimulation of muscle tissue (called neuromuscular electrical stimulation) around the shoulder may be useful for strengthening the muscles that support the joint and relieving pain in and around the joint. In the shoulder, this technique may be a helpful adjunct to surgical treatment for rotator cuff tears. A number of studies have shown the treatment to be effective, however, studies have focused specifically on the treatment for knee osteoarthritis.

Assistive devices. When your shoulders are stiff or painful it can be hard to perform daily tasks, such as bathing, getting dressed, driving or reaching for items in your kitchen cabinets. Many devices are available to make these activities easier, including reachers, zipper pulls, long-handled brushes or sponges and specially designed adaptive clothing. You can buy many assistive devices through medical supply stores and specialized mail-order catalogs. Talk to your doctor and physical and/or occupational therapist about using these assistive devices.