Some of the most common causes of numbness in the shoulder are medical conditions such as neuropathy or diabetic neuropathy. A condition known as thoracic outlet syndrome may also produce numbness in the shoulder, along with other symptoms such tingling of the fingers. Rotator cuff injuries, as well as pinched nerves, are other common causes of numbness in the shoulder area. Multiple sclerosis may also cause these and other symptoms. Poor circulation in the shoulder area may cause numbness in the shoulder as well.

When an individual suffers from numbness in the shoulder, he may associate this with overexertion or repetitive-motion injury. This may be a possibility, although other symptoms may accompany this type of injury, such as swelling and pain. One common cause of shoulder pain, tingling, or numbness is shoulder tendinitis. Often this is caused by repetitive-motion stress.

Tendinitis of the shoulder area occurs when tendons become stretched and inflamed, typically due to over usage. Many individuals employed in occupations that require overhead lifting or extending the arm repeatedly suffer from shoulder tendinitis. Symptoms of shoulder tendinitis are pain, swelling, tenderness, tingling, and numbness in the shoulder. Doctors may advise rest, ice, and shoulder exercises as part of a therapy program to treat this condition.

A rotator cuff tear is another common cause of numbness in the shoulder. The rotator cuff is located in the upper region of the arm, or directly at the top of the shoulder. It is made up of several muscles and tendons, which attach to bone. The rotator cuff may become torn through repetitive-motion injury or acute injury to the shoulder.

Severe pain and immobility may be most common symptoms of this type of injury, although numbness may often occur as well. If the rotator cuff tear is significant enough, it may require surgery to repair. Arthroscopic surgery, typically performed using a device known as an arthroscope, may be one option.

A disease of the central nervous system known as multiple sclerosis may cause muscle weakness and paraesthesia. This may produce partial numbness in the shoulder and other areas of the body. In more severe cases, complete numbness of the shoulders and neck may occur.

For some individuals with nutritional deficiencies, poor blood circulation may occur. This may result in numbness that affects various areas of the body, including the limbs and shoulder area. Left untreated, poor blood circulation may result in high blood pressure, heart disease, or diabetes. This is why unexplained numbness of the shoulder area without apparent cause should be diagnosed by a medical professional.