Common Causes of Shoulder Pain
There are many potential causes of shoulder pain, both chronic and acute. A proper diagnosis is crucial to ensuring you receive the most effective treatment for your condition.
In some instances, your shoulder pain may be caused by an injury associated with a one-time event. These include:
- Fractures – a sudden blow to the shoulder may cause a break in one of the bones at the joint and damage the nerves or blood vessels in the area. Fractures most commonly occur in vehicle accidents, sports injuries, and serious falls. Possible fracture sites are:
- Humerus – most commonly due to a fall on an outstretched hand
- Clavicle – usually due to a direct blow to the shoulder or chest
- Dislocations – occurs when the humerus gets knocked out of its socket. This injury also occurs with vehicle accidents and serious falls. The surrounding ligaments and muscles can be damaged with this type of injury.
- Anterior dislocation: The most common type of dislocation at the shoulder joint. The humerus (upper arm bone) is pushed forward out of the socket.
- Posterior dislocation: The humerus is pushed backward out of the shoulder socket.
- Subluxation: This is a partial dislocation where the humerus has been partially pushed out of the socket.
- Sprains and strains – Stretched or torn ligaments result in a sprain, as do stretched or torn muscles. These injuries occur when you place too much pressure on your muscles and ligaments. Most common when lifting heavy objects overhead, participating in sports, or with a dislocation.
Repetitive motions can result in significant wear and tear to your shoulder. These injuries often occur in work environments or from athletic activities, and they can be quite painful. Common examples of repetitive motion injuries include:
- Bursitis – The bursa can fill with fluid and become swollen, causing redness and sensitivity. Damage can occur from overuse or from trauma to the joint. This causes pain at the outside of the arm-shoulder junction.
- Tendonitis – The tendons in your shoulder can become impinged or damaged from overuse or lifting heavy loads, causing painful inflammation.
- Rotator cuff tendonitis – the tendon of the supraspinatus muscle is compressed beneath the acromion. This is common and often seen with repetitive flexion of the shoulder.
- Rotator cuff tear – a common condition due to overuse in overhead activities, as a progression of tendonitis, or with acute trauma to the shoulder.
- Cartilage damage – The most common type of cartilage damage in the shoulder involves the labrum. This cartilage in the joint acts as a cushion, allowing smooth movement between the humerus and the glenoid.
- Overuse – often due to repetitive overhead activities (often sports-related), this may be painless or can cause pain, instability, and “catching” in the shoulder.
- Osteoarthritis – a slow, progressive degenerative process where the cartilage breaks down.
- Adhesive capsulitis – AKA frozen shoulder. This typically results from chronic, long-term inflammation of the shoulder.
Damage to nerves in the shoulder are uncommon, but can occur:
- Nerve Pain – Usually caused by nerve compression, it is often associated with numbness, tingling, or burning sensations that can extend down to the arm and hand. In severe cases, you may experience weakness of the arm.
- Axillary Nerve Compression – the axillary nerve is pinched as it crosses under the humerus in the armpit area.
- Thoracic Outlet Syndrome – compression of the brachial plexus (a bundle of nerves from the neck to the shoulder area) between the neck and the armpit can cause pain in the neck, shoulders, and arm on the affected side. Usually seen in people with an anatomic predisposition. These include:
- Muscle abnormality – the scalene muscles in the neck can become large (hypertrophy) and compress the nerves as they traverse the muscle.
- Bone abnormality – some people have an extra rib in the neck, called a “cervical rib”, which impinges the brachial plexus. Collarbone dislocations can cause impingement as well.
- Chronic overuse – especially with overhead activities. Also seen in athletic endeavors such as swimming and rowing.
Arthritis can develop from inflammation of the shoulder joint, causing pain and stiffness which gets worse over time. The most common types of arthritis impacting the shoulder include:
- Rheumatoid arthritis – This occurs when your immune system attacks your joints, causing swelling and pain.
- Osteoarthritis – This develops when the cartilage in your shoulder breaks down, causing the bones to rub together. Osteoarthritis results in pain and stiffness.
- Acromioclavicular Joint – occurs when the surrounding cartilage deteriorates. It can cause pain at the top point of your shoulder.
- Glenohumeral Joint – less common, this occurs at the junction of the humerus with the glenoid. It can cause pain in the back of the shoulder.