ANATOMY OF A SHOULDER
Shoulder, the most movable joint in the body, includes four bones –
- The humerus (arm bone)
- The clavicle (collarbone)
- The scapula (shoulder blade)
- The sternum (breastbone).
The primary shoulder joint, technically known as the gleno-humeral joint, is a typical modified ball and socket joint. In this a “ball” in the upper humerus fits against a shallow, disc-shaped socket in the scapula. A soft-tissue envelope known as a capsule encircles the gleno-humeral joint and is lined by a thin, smooth synovial membrane.
Additional joints in both shoulders include:
- Acromioclavicular (AC) joint
Several ligaments and a cartilaginous disc connect the acromion (the highest point of the shoulder at the top of the scapula) and the clavicle. The AC joint is often injured in collision sports such as football and bicycling.
- Sternoclavicular joint
Several strong ligaments connect the clavicle to the sternum near the body’s midline. This synovial joint is the most stable and least injured of the shoulder joints.
Muscles, tendons and ligaments keep the bones of the shoulder in place. Ligaments attach the shoulder bones to each other, and the tendons attach the bones to the shoulder muscles. These soft tissues help the muscles move the shoulder.
Other important structures of the shoulder include the rotator cuff, which is a combination of tendons and muscles that holds the “ball” of the humerus against the shallow socket of the gleno-humeral joint. This helps provide great mobility and strength to the shoulder joint.
In addition, two filmy, sac-like structures called bursae help bone, muscle and tendon to work together smoothly while minimizing friction. The bursae protect the rotator cuff form the bony arch of the acromion.
The shoulder’s anatomy allows a wide range of motion. However, this flexibility also makes the joint unstable and prone to injury.
WHAT CAUSES SHOULDER PAIN?
The multiple types of movement of the shoulder render it vulnerable to various types of injuries or changes that cause pain. The pain could result from an injury, degenerative disease, or wear and tear from overuse or aging that damages the soft tissues (including the muscles, tendons and ligaments), bones of the shoulder joint or the area around it. These tissues must remain healthy and strong if they are to keep the shoulder joint anchored, stabilized and working properly. If these tissues become damaged, shoulder pain can result. The pain could be due to shoulder sprains, strains, dislocations or other problems.
Shoulder pain is the discomfort that affects any part of the shoulder joint or the area surrounding it. The cause of this could be trauma, degenerative disease, underuse, overuse or aging.
WHAT CAUSES SHOULDER PAIN?
Shoulder pain may be localized, meaning that it is confined to a specific area or it may be more widespread, affecting areas throughout the shoulder and even into the neck, back or arm.
In some cases shoulder pain may emanate from the heart and spread towards the right or both shoulders. This pain may be relieved by resting and is called Angina Pain.
Shoulder pain varies depending on the nature of the injury, degenerative process or abuse that is the source of the pain. Common causes of shoulder pain include:
Shoulder injuries of this type pull the shoulder outward or an extreme rotation of the shoulder pulls the ball of the humerus (long bone of the arm extending from the shoulder to the elbow) out of the shallow socket. These are the most common major dislocations in the body. In most cases, a dislocation occurs due to some force (such as a fall or sports injury) and often occurs when a backward pull on the arm overwhelms the supporting muscles.
The dislocation could be complete or partial. In partial dislocation part of the ball remains against the socket and is known as a subluxation. A few patients may experience minor subluxation followed by reduction itself. Subluxation, sometimes painful, can also result from neurovascular conditions such as stroke.
Shoulders can dislocate in several directions – forward, backward or downward. Dislocation usually causes pain that may be intensified when accompanied by muscle spasms. Swelling, numbness, weakness and bruising are common. Associated ligament (tough, fibrous tissue connecting bones or cartilage at a joint or supporting an organ) or tendon (tough, inelastic fibrous tissue that connects muscle with its bony attachment) damage and – less frequently – nerve damage also occur, though less frequently.
It occurs in the area where the collarbone (clavicle) and the shoulder blade (scapula) meet. Ligaments that hold the joint together may become partially or completely torn, causing the outer end of the clavicle to slip so that it does not properly join with the scapula. Blows to the shoulder or falling with an outstretched hand are the most common causes of shoulder separations.
People who suffer a shoulder separation experience pain and tenderness, usually over the acromioclavicular (AC) joint between the acromion and the clavicle especially when the shoulder is moved. In some cases, a bump may form in the middle of the shoulder over the acromioclavicular joint. The AC joint can be palpated by moving fingers over the collarbone from medial (near the center of the body) to lateral (away from the center of the body).
- Torn Rotator Cuff
The rotator cuff is made up of the muscles and tendons that connect the humerus to the shoulder blade. Tendons in the rotator cuff are normally strong, but they can become inflamed and tear as a result of overuse, wear and tear associated with aging or an accident such as a collision. Sports that require repeated overhead motion (e.g., pitching in baseball) and occupations that require heavy lifting are primary sources of rotator cuff tears. Usually patients may have difficulty raising their arm above the shoulder (90 degrees). Small tears may go unnoticed.
- Tendinitis, Bursitis ans Impingement Syndrome
These three closely related conditions can occur separately or in combination. They are sometimes grouped under the heading of an injured rotator cuff. The three conditions are:
Tendinitis or Inflammation of a tendon
In the shoulder, tendinitis is most likely to affect the tendons of the rotator cuff or biceps as a result of pinching from surrounding structures.
When tendinitis affects the rotator cuff, the inflamed and thickened tendon may become trapped under the acromion. This squeezing of the rotator cuff is called impingement syndrome.
Bursitis or Inflammation of the Bursae
These sacs protect the shoulder and help make movement more fluid. However, they can become inflamed either separately or in tandem with tendinitis and impingement syndrome.
Repetitive motions involving the arms or wear and tear over many years can irritate or wear down tendons, muscles and surrounding tissues. Sports involving overuse of the shoulder and jobs that require excessive overhead reaching are sources of these disorders. In addition, they may be caused by diseases such as rheumatoid arthritis.
Tendinitis, bursitis and impingement syndrome may cause a slow onset of discomfort or pain in the upper shoulder. The pain may travel down the arm to the elbow and forearm also. Some patients report difficulty sleeping on the shoulder. In addition, tendinitis and bursitis often cause pain when the arm is lifted away from the body or overhead. Strong pain may be felt if the arm or shoulder is pushed forcefully up, forward or backward. Patients with these conditions often have limited shoulder mobility.
A partial or total crack through a bone, frequently as the result of a fall or blow to the shoulder may occur. Fractures often involve the clavicle or the neck of the humerus, which is the area just below the ball. Although a fracture may not be a major injury, it usually results in severe pain accompanied by redness and bruising.
Fractures can be closed or open (breaking the skin), as well as avulsion, compression or impact. Osteoarthritis is the most common type of arthritis and is caused by joint cartilage deterioration.
- Arthritis of the shoulder
It is a degenerative disease caused by either wear and tear of the cartilage (osteoarthritis) or inflammation of one or more joints (rheumatoid arthritis). Ankylosing spondylitis, a form of arthritis that primarily affects the spine, can also cause shoulder pain. Arthritis also affects supporting structures, including muscles, tendons and ligaments. People with arthritis of the shoulder experience pain – typically over the AC joint – and decreased shoulder mobility.
- Osteophytes or Bone Spurs
These are often caused by degenerative changes such as osteoarthritis. Bony projections can restrict the shoulder’s range of motion and cause pain.
- Adhesive Capsulitis or Frozen Shoulder
This condition causes pain that severely restricts the patient’s ability to move the shoulder. Patients may be unable to raise their arm without feeling significant pain, and stiffness and pain may worsen at night. Injuries are a common source of frozen shoulder, but it also can result from rheumatic diseases and shoulder surgery. Hallmarks of this condition include inflammation, abnormal bands of tissue between the joint surfaces and a lack of synovial fluid (which normally provides lubrication to the gap between the humerus and its socket). People with diabetes, stroke, lung disease, rheumatoid arthritis and heart disease are at greater risk for frozen shoulder.
- Heart Attack
Pain radiating from the chest to the shoulders, arms, neck or jaw may signal a heart attack (myocardial infarction). A heart attack can also cause shoulder pain without chest pain. Patients suspecting a heart attack are urged to seek immediate medical attention.
- Pinched Nerve
Nerves can be compressed throughout the body. Examples that affect the shoulder include impingement of the axillary nerve in the armpit, which can result from use of crutches, and subscapular nerveentrapment, an uncommon condition caused by restriction of the subscapular nerve.
- Heavy backpacks
Researchers have found that many schoolchildren use excessively heavy or poorly positioned backpacks, which can injure the shoulders and back.
- Thoracic Outlet Syndrome (TOS)
It is a name given to several unrelated disorders, some of them controversial and ill-defined that affects blood vessels and nerves in the region between the base of the neck and the armpit. Symptoms can include shoulder, neck and arm pain and weakness. True neurologic TOS, caused by atypical anatomic features that are present at birth, is rare and can be treated surgically. Other forms of TOS can be treated symptomatically.
It is an injury to the soft tissues of the neck resulting from a sudden jerking of the head. In addition to neck pain, whiplash may cause shoulder pain, back pain and headaches.
Whiplash is a neck injury caused by abrupt jerking motion of the head (as with a car accident).
- Polymyalgia Rheumatica
It is a chronic inflammatory disease marked by muscle pain and stiffness around the neck, shoulders and hips.
Though rare, infection can be another source of pain and inflammation.
- Referred pain
Pain from the neck can be felt in the shoulder. Ectopic pregnancy (implanted outside the uterus) and certain conditions of the gallbladder, liver or diaphragm can be experienced as shoulder pain.
WHAT ARE THE COMMON TESTS PERFROMED TO DIAGNOSE SHOULDER PAIN?
As in diagnosing any other disease the attending physician initially reviews the patient’s medical history. A physical examination is conducted to:
- Feel / palpate the shoulder to detect physical signs of any injury.
- Assess range / limits of shoulder movement.
- Identify the extent of joint instability or stiffness.
- Carry out pain assessment.
In some cases, further testing will be necessary to pinpoint the cause of shoulder pain. Such tests may include:
- X-ray imaging
X-ray pictures may reveal more detail about the cause of pain. For example, the severity of a shoulder separation can be detected by taking an x-ray of the shoulder while the patient holds a light weight. This pulls on the muscle and makes the separation even more pronounced. Traditional x-ray procedures cannot reveal all injuries.
This x-ray procedure uses a dye or a contrast medium injected into the joint to outline the structures of the shoulder. The contrast fluid can indicate tears, openings or blockages.
- MRI (Magnetic Resonance Imaging)
A MRI provides cross-sectional images of the shoulder. It can be used to detect rotator cuff injuries and degenerative conditions of the shoulder, neck or spine. MRI or other imaging tests can sometimes avoid the need for arthroscopic examination.
- CAT scan (Computed Axial Tomography)
This test using multiple x-rays can detect many disorders of the joints, bones, muscles and internal organs.
- Bone Scan or Other Radionuclide Imaging
Nuclear medicine can be used to detect conditions such as bone diseases, hidden fractures and cancer.
- Blood tests
These may be ordered if infection or certain other conditions are suspected.
A camera is inserted in the joint and the condition of the joint visualized outside. This procedure is usually done under general anesthesia and is performed when other diagnostic measures fail to make a diagnosis.
WHAT IS RICE- FOUR STEP REGIMEN- FOR TREATING SHOULDER PAIN?
Rice is a four step process for treating shoulder pain. It involves-
Reduce usage or stop using the affected joint for 48 hours.
Provide cold therapy by using an ice pack over the injured area for 20 minutes at a time. This can be applied for 3 to 4 times with a time span separation of at least 15 minutes between each application. Do not apply ice directly to the skin- use an ice pack or a towel/cloth instead.
To reduce swelling use bandages or an elastic wrap around the shoulder.
Keep the affected shoulder raised above the level of the heart by placing a pillow underneath.
In most cases this will help in healing the shoulder. OTC pain and anti-inflammation drugs will help improve the symptoms.
WHEN IS PROFESSIONAL MEDICAL HELP NECESSARY TO TREAT SHOULDER PAIN?
Professional medical help must be sought if:
- Pain lasts for more than 2 weeks despite home care measures.
- An injury or severe blow causes:
- Pain and swelling.
- Significant bruising.
- Suspected fracture.
WHAT TREATMENT IS PROVIDED FOR A DISLOCATED SHOULDER?
Each problem of the shoulder is treated differently. The dislocated ball of the humerus (long bone of the arm extending from the shoulder to the elbow) is pushed back into the socket. This procedure is known as a reduction. Intravenous (I.V.) medications can be given before reduction to reduce any discomfort. The arm is then immobilized in a sling or a shoulder immobilizer for a few weeks. Patients are often urged to apply ice to the shoulder three or four times each day.
Once pain and swelling have been controlled, the patient may enter a rehabilitation program. In some cases, a shoulder that has dislocated becomes more susceptible to the same injury in the future. Surgery may be necessary to correct this flaw.
IS SURGERY NECESSARY FOR TREATING SEPARATION OF THE SHOULDER?
Generally rest and physical therapy are provided for treating separation. The affected arm is put in a sling and the patient is advised to rest the shoulder. Within about 2 to 3 months full healing occurs. A short period of physiotherapy or occupational therapy may be provided thereafter. In cases where severe damage to the ligaments due to ligament tear has occurred, surgery may be advised.
HOW IS TENDINITIS TREATED?
Tendinitis, bursitis and impingement syndrome require rest and cold therapy (cyrotherapy). Anti-inflammatory drugs are also used to cure these conditions. Thermotherapy and/or therapeutic ultrasound may be used to warm deep tissues and stimulate blood flow.
Corticosteroid injections may be administered to the affected shoulder, in case no relief is available from other measures. Chronic tendonitis may result in rupture of a tendon. In cases where no improvement is noticed after 6 to 12 months of treatment, surgery may be required to repair the tendon.
HOW EFFECTIVE IS CRYOTHERAPY- COLD THERAPY- FOR A TORN ROTATOR CUFF?
Torn rotator cuff is treated with the following measures:
- Rest the affected shoulder.
- Apply heat or cold to sore areas.
- Electrical stimulation of muscles and nerves.
- Therapeutic ultrasound.
- Corticosteroid injections.
- Evaluation for correcting the faulty action (heavy lifting or sports movement) that caused the injury.
- Arthroscopy or other surgery to repair severe tears.
Physical or occupational therapy is advised after the rotator cuff has healed. It helps in correcting the fault and restore range of motion.
WHAT IS THE LIKELIHOOD OF SURGERY FOR A FRACTURED SHOULDER?
It is essential to first bring the bone back in to position to speed the healing process and restore arm movement- though up to limited extent in most cases.
For a non displaced fracture of the clavicle (collarbone), wearing a strap or string is usually not recommended. When the clavicle is involved, a strap or sling around the chest is recommended to be worn. The basic aim of the strapping is to keep the clavicle in place.
Fracture of the neck of the humerus is usually treated with a sling or shoulder immobilizer. Some cases, depending on the severity and location of the fracture, may require surgery to set the fractured bone.
WHAT OTHER TREATMENTS ARE AVAILABLE FOR SHOULDER PAIN?
Treating other causes of shoulder pain depends on the cause of pain. This could be:
- Frozen Shoulder
Thermotherapy coupled with anti-inflamatory drugs is the usual treatment option for a frozen shoulder. Some stretching exercises are also generally advised. Nerve impulses may be blocked to reduce pain by using Trans- cutaneous electrical nerve stimulation (TENS). Surgery may be required in a few cases. Physical and occupational therapy will be introduced to improve the range of movement of the shoulder and control pain.
- Arthritis of the Shoulder
Treatment depends on the type of arthritis present.
Osteoarthritis caused by wear and tear of the joints in old age, is treated with non steroidal anti-inflammatory drugs. Rheumatoid arthritis usually requires occupational therapy and additional medicines. Injecting corticosteroids into the joint provides temporary relief from pain.
Surgery is carried out to repair the affected shoulder joint. Typically replacement of the worn shoulder joint is undertaken during surgery. An artificial ball for the top of the humerus and a cap (glenoid) for the scapula (shoulder blade). The success of the joint replacement surgery is dependant upon:
- The condition of the rotator cuff muscles before the surgery.
- Cooperation of the patient in following the rehabilitation therapy.
Shoulder pain may sometimes be indicative of a more serious underlying health condition. Sudden shoulder pain may be caused by a heart attack. Patients must seek immediate medical care if, they experience sudden pressure or crushing pain in the shoulder, especially if the pain radiates towards the chest, jaw, neck or down the arm. Pain accompanied by shortness of breath, dizziness or sweating also requires immediate medical care.
IS IT POSSIBLE TO PREVENT SHOULDER PAIN UP TO SOME EXTENT?
It may not be always possible to prevent shoulder pain- sudden injury or degenerative disorder can generally not be prevented. Recurrence of old injuries or likelihood of new injuries can be controlled to a certain extent. Some of the steps towards this are:
- Correct Posture
Adopting and practicing correct posture and ergonomics at work and at home reduces the risk of repetitive strain injuries and sudden trauma. Forearm support boards may prevent shoulder, arm and neck pain and injury in computer users.
Using an ice pack and anti-inflammatory drug like ibuprofen, especially after exercise may help in preventing recurrence of pain.
Seeking the guidance of a physiotherapist / occupational therapist or a physician to develop a need specific exercise schedule to stretch and strengthen rotator cuff tendons (tough inelastic fibrous tissue connecting muscle with its bony attachment) and shoulder muscles.
Performing range of motion exercises when recovering from tendonitis helps prevent frozen shoulder.
- Proper technique
Learning and adopting proper technique for participating in an athletics or contact sport event prevents shoulder problems.
- Warm up exercises
Stretching and body warm up exercises before and after a strenuous athletics activity helps reduce chances of an injury