The shoulder is a complex structure capable of a wide range of motion, so it’s no wonder that pain and functional issues with the shoulder are quite common. The shoulder is made up of two joints and a number of muscles, bones, tendons, ligaments and bursa.
The two joints in the shoulder are the glenohumeral joint (the joint between the upper arm [humerus] and shoulder blade [scapula]), and the acromioclavicular joint (the connection between the top of the shoulder blade [scapula] and the collarbone [clavicle]).
Between these two joints are a number of strong, flexible ligaments and connective tissues forming what is called the “shoulder capsule”. The tendons of the rotator cuff also blend with the capsule. This structure helps keep the humerus in place and provides the shoulder with stability during range of movement. The capsule is encased within a special membrane (the synovium) that produces a lubricating fluid (synovial fluid) that both nourishes the joint and keeps it moving smoothly.
Combined, the two shoulder joints allow for the widest range of motion of any joint in the body. With this increased mobility, comes a need for increased stability. This motion is provided by the rotator cuff, the four tendons that connect muscles to the bones comprising the shoulder.
Due to the complexity of the shoulder, the number of constituent parts, and the wide range of motion the structure is capable of, injury to the shoulder is quite common. Disease and other health conditions may also affect the function or range of motion of the shoulder.
Arthritis: Osteoarthritis, Rheumatoid Arthritis and Septic Arthritis
Arthritis is not a single disease but rather a name for more than 100 different diseases and conditions that cause joint pain and inflammation. The three most common forms of arthritis of the shoulder are osteoarthritis and rheumatoid arthritis.
- Osteoarthritis - osteoarthritis is the most common form of arthritis diagnosed and occurs when the protective cartilage at the end of bones degenerates and wears away. The degeneration of the cartilage may be caused by acute or chronic trauma, disease, biomechanical issues or simply growing older.
The loss of this protective cartilage may lead to pain and stiffness in the joint, inflammation, a loss of flexibility and an unpleasant grating sensation in the joint.
- Rheumatoid Arthritis - rheumatoid arthritis (RA) is a chronic autoimmune disease that causes inflammation and pain in the joints. The presentation of rheumatoid arthritis is typically bilateral, so if you have RA in one shoulder you will most likely have it in the other as well.
Symptoms of RA include pain, inflammation, joint stiffness and reduced range of motion. Even though rheumatoid arthritis is an incurable, chronic (long term) condition, that does not mean the symptoms are always severe or even present. RA goes through periods of flare or exacerbation as well as pain-free periods of remission.
The trigger for flares may vary from person to person and may include temperature, humidity, foods, medication, stress, exposure to chemicals, mood, physical activity, injury, infection or nothing readily identifiable.
- Septic Arthritis - inflammation and pain in a joint caused by infection.
A condition that commonly presents as a symptom of rheumatoid or osteoarthritis, synovitis is an inflammation of the synovial membrane that helps protect, nourish and lubricate the shoulder capsule.
This inflammation may lead to a buildup of synovial fluid within the shoulder, leading to pain and stiffness in the joint. The pain associated with synovitis is usually more intense than would be expected from the appearance of the affected joint, as the pain may be severe without the outward presentation of inflammation or injury.
While synovitis is a common comorbidity with arthritis, the condition may also be caused by injury or overuse of the joint.
Frozen Shoulder (Adhesive Capsulitis)
Frozen shoulder, also known as adhesive capsulitis is a condition typified by a reduced range of motion and pain in the shoulder. It occurs when the synovial membrane that encases the shoulder capsule thickens and constricts the capsule, restricting movement.
There is no readily identifiable cause of frozen shoulder, but people living with diabetes, or those that have had their shoulder immobilised for long periods (such as in the case of a broken arm or following a mastectomy), may have an increased risk of developing this condition.
Frozen shoulder typically occurs in three stages:
- Freezing - as the membrane thickens the range of motion in the shoulder progressively diminishes and every movement of the shoulder causes pain.
- Frozen - the shoulder has stiffened significantly and using it becomes difficult. Pain may recede at this point.
- Thawing - the range of motion in the shoulder begins to improve. Pain may increase during this phase as the formerly frozen shoulder begins to move freely.
Some people may find the pain becomes worse at night, to the point it may disrupt sleep patterns.
In many cases, the progress from freezing to thawing may take between one to three years, but for others, it may take far longer, with the frozen stage lasting for years, or even perpetually.
A shoulder sprain is a stretched, twisted or torn ligament. They are typically caused by a joint being stressed by a fall, impact or rotation and the ligament being stretched or torn as a result.
A shoulder strain refers to stretched, twisted or torn muscle fibres or tendons. Strains may be acute (sudden) or chronic (develop over time) due to repetitive movement, overexertion (such as experienced when lifting heavy objects), impact or injury, or being in an awkward physical position for long periods of time.
Learn more about the difference between a strain and a sprain.
The labrum is a piece of cartilage that is attached to the edge of the shoulder socket. This lip of rubbery tissue helps keep the ball of the joint in place, by deepening the shoulder socket. If this ring of cartilage is torn, a person with a labral tear may experience pain, a reduction in shoulder movement, a grinding sensation in the shoulder, or popping, catching or locking during movement. A loss of “stability” in the shoulder (such as reduced strength or ability to take weight) may also be experienced.
There are three major forms of labral tears:
- SLAP Tear - SLAP is an acronym for “Superior Labrum, Anterior to Posterior”, or in other words, a front to back tear. Most commonly diagnosed in people who frequently perform arm motions over the head, such as tennis and basketball players.
- Bankart Tear - these tears occur in the lower part of the glenoid socket (the ball and socket joint that joins the humerus to the scapula) and are commonly caused by shoulder dislocations.
- Posterior Labrum Tear - these tears occur in the back of the labrum and are quite rare, accounting for only 5%-10% of all labral tears.
Rotator Cuff Injury (Rotator Cuff Disease)
The rotator cuff is a group of four muscles and the attached tendons that surround the shoulder joint and serve a dual purpose of keeping the ball of the joint in its socket as well as providing motion to the shoulder.
Rotator cuff disease may be caused by a number of factors, including injury or progressive degeneration to the tendons caused by overuse or age. Typical symptoms include a dull ache in the shoulder, a loss of arm strength and restricted range of motion, especially above the head or behind the back.
As the shoulder is the most mobile joint in the body, it is also prone to dislocation. A dislocated or subluxed shoulder occurs when the ball of the humerus slips from the socket in the scapula. This is typically caused by impact or injury, such as a fall, car crash, or impact sustained while playing contact sports like rugby league or union.
Symptoms of a dislocated shoulder are typically readily apparent and immediate and include a notable deformation of the shoulder, intense pain, an inability to properly use the arm, inflammation and bruising. Due to the nature of the injury, it’s not uncommon for the dislocation to cause tearing to the surrounding muscles, tendons and ligaments, damage to blood vessels and/or nerves in the shoulder, and making the shoulder more prone to further dislocation in the future.
Axillary Nerve Dysfunction
The axillary nerve carries nerve impulses to three muscles in the shoulder - the deltoid muscle, triceps and teres minor - as well as carrying sensory signals from the shoulder joint to the brain. Damage to the axillary nerve may lead to Axillary Nerve Dysfunction (AND).
Typical symptoms of AND include numbness or tingling in the shoulder, weakness in the shoulder, and an inability to raise the arms above the head or lift heavy objects. Axillary nerve damage may be caused by impact or injury, such as a fall or gunshot wound, excessive stress or microtrauma to the nerve over a long period of time (such as someone who uses a crutch for long periods compressing the nerve), or by hyperextending or dislocating the shoulder.
Neck and Upper Back Nerve Impingement
Pain in the shoulder may not be caused by the structure itself but rather by the nerves supplying the area. An impinged nerve, also referred to as a pinched nerve is one that has been compressed as it leaves the spinal column, typically due to a herniated disc, fractures due to osteoporosis or other spinal issues.
Symptoms of an impinged nerve include pain and a feeling of pins and needles or numbness. These symptoms don’t change depending on the position of the shoulder due to the pain originating elsewhere in the body. That said, some body positions, such as lying on your back to sleep or sitting with poor posture may cause the symptoms to worsen as pressure on the nerve is increased.
Book an appointment to see your GP, or schedule a consultation with a physiotherapist to relieve pain and get your shoulder back in shape once again.
Pain in the shoulder that doesn’t change due to the position of the joint may be referred pain, a condition in which the pain is caused by something in another part of the body.
Depending on the underlying cause, the symptoms of referred pain may be described as an electric, burning or tingling sensation in the shoulder, a sharp pain under the shoulder blade, a dull ache or a pain that travels from your shoulder to neck or vice-versa. The symptoms are typically constant, not related to positioning or movement.
Typical causes of referred shoulder pain include abdominal and pelvic issues such as gallstones, pancreatitis, ruptured ovarian cysts or air trapped in the abdominal cavity due to laparoscopic surgery or gynecological procedures. Other causes of referred shoulder pain include heart and blood vessel problems (typically appearing in the left shoulder), lung issues such as pneumonia , and shingles (herpes zoster) .
Bursae are small, fluid-filled sacs that help reduce friction and help cushion pressure points between bones, tendons and ligaments in joints. Bursitis is inflammation of the bursae. In the shoulder, the bursa acts as a shock absorber and cushion for tendons. If the bursa becomes inflamed due to injury, infection, overuse or repeated microtrauma, a person with bursitis may experience pain when moving, sleeping on or otherwise putting pressure on the shoulder, as well as a reduction in range of motion.
Shoulder tendinopathy is the acute or chronic degeneration of a tendon due to overload, tears or other traumas. The cause of tendinopathy is typically injury (falls, strains, etc) or repeated microtrauma, from applying a load to the tendon, over its capacity. Tendinopathy typically causes pain, a reduction in range of motion and often weakness.
People who play sports like baseball, tennis or golf, or swim frequently or competitively commonly develop shoulder tendinopathy, but anyone with a job or pastime that sees them performing overhead arm motions, or picking up and carrying heavy objects may also be at risk.
Due to similar risk factors, tendinopathy and bursitis in the shoulder frequently appear together.
Bone spurs are excess bone growth on the edge of a bone, typically near a joint. Despite the name, bone spurs are usually smooth formation of bone rather than jagged, but this doesn’t mean they can’t cause problems.
Most people will develop bone spurs as they age, and many of those will not notice them in any way, but for some people bone spurs may reduce the mobility of a joint or rub against the surrounding tissue leading to tendinitis.Osteoarthritis is the most common cause of bone spurs in the shoulder. As the protective cartilage wears away, so too does the bone in the joint. In response to this damage, the body grows new bone near the damage. Bone spurs in the shoulder may cause pain and inflammation, a loss of mobility or strength, tendinopathy or rotator cuff injuries.
A shoulder fracture is a break in one or more of the bones in the shoulder. There are three types of shoulder fracture:
- Clavicle - the clavicle is the long bone that runs across the shoulder to the sternum. Fractures of the clavicle are typically caused by sudden impact such as sports injuries from clashes, falls from a road bike, car accidents or falls. Inflammation and bruising, pain and an inability to lift the arm are common symptoms of a clavicle fracture.
- Proximal Humerus - a proximal humerus fracture is a fracture of the top of the humerus (arm bone), either at or just below the ball joint. This type of fracture is common in older people but may occur at any age. Fracture of the proximal humerus is the third most common non-vertebral fracture in people over 65. Women are around twice as likely to suffer proximal humeral fractures than men.
- Scapula - the scapula is the large, triangular bone at the back of the shoulder, often referred to as the shoulder blade. Scapular fractures are rare and typically occur in men between the ages of 25 and 45. The most common causes of scapula fractures are sporting injuries sustained playing contact sports, and car accidents. The force required for a fractured scapula is very high, so people presenting with a fractured scapula also frequently have other injuries, such as broken ribs or lung damage.
If you’re experiencing shoulder pain and it is impacting your ability to function, don’t put off getting some treatment. Ignoring the problem may make it worse, or may negatively impact your quality of life. Book an appointment to see a doctor or schedule a session with a physiotherapist to get some relief. The fastest and easiest way to search for and book healthcare appointments online is through MyHealth1st.