There are a number of injuries and conditions that can potentially cause shoulder pain and weakness. Some of these may cause weakness in only the shoulder joint while others may affect muscles throughout the body. Examples of problems that can affect the muscles surrounding the shoulder joint include inflammation; hypothyroidism, which is a disease affecting the thyroid; and rotator cuff tears. Conditions that can affect the nerves connecting to the shoulder joint include diabetes and infections.
Shoulder pain and weakness can either be caused by a direct injury to the muscles surrounding the joint or a condition that affects how the muscles work. Myopathy is the name given to any disease or condition that affects the function of the muscle. Neuropathy is used to describe conditions that affect the nerves connecting to the muscle. When certain nerves don’t fire correctly then the muscles surrounding the joint will atrophy over time and cause muscle weakness.
Rotator cuff tears and strains are among the most common injuries to the shoulder. The rotator cuff is actually a set of muscles that encase the shoulder and help to perform a number of activities including lifting. When a tear occurs to a tendon attaching to one of these muscles, then the shoulder will weaken. Shoulder pain and weakness may become permanent if a rotator cuff tear is not treated correctly and within a reasonable time frame.
Shoulder inflammation of any kind can also cause a weakness. Inflammation can be a symptom of a range of problems including bursitis. When inflammation in a joint occurs, the body takes steps to limit the damage. In some cases this may involve not providing full strength to muscles surrounding the joint. Inflammation also causes pain.
There are a number of diseases and more serious conditions that can cause shoulder pain and weakness. Many of these will cause weakness in muscles throughout the body and not just around the shoulder. For example, polymyositis is a chronic condition that causes inflammation in muscles around the body and becomes more noticeable in adulthood. Shoulder pain and weakness can also be caused by mitochondrial disease.
Treatment for shoulder pain and weakness depends on the cause. For injuries such as a rotator cuff tear, conservative physiotherapy or surgery may be used in order to heal the tendon. If the condition is caused by inflammation then anti inflammatory medicine can help.
