Muscle weakness in your arms can have a number of causes, ranging from common conditions like a pinched nerve in the neck, to rarer conditions such as brachial plexopathy (shoulder nerve issue). Read more below to learn what may be making your arms feel weak.
5 causes of weakness in both upper arms
This list does not constitute medical advice and may not accurately represent what you have.
Pinched nerve in the neck
A pinched nerve in the neck is also called cervical radiculopathy. It means that a nerve in the neck, at a point where it branches off from the spinal cord, is being compressed by the surrounding bones, muscles, or other tissues.
It can be caused by a traumatic injury, such as from sports or an automobile accident, especially if the injury results in a herniated disk. It may also arise from the normal wear and tear of aging.
Symptoms include sharp, burning pain with numbness and tingling from the neck to the shoulder, as well as weakness and numbness into the arm and hand.
Diagnosis is made through patient history, physical examination, and simple neurological tests to check the reflexes. Imaging such as x-ray, CT scan, or MRI may be done, as well as electromyography to measure nerve impulses in the muscles.
A pinched nerve in the neck often improves with simply a few days or weeks of rest. Physical therapy, nonsteroidal anti-inflammatory drugs, and steroid injections into the spine can all be very helpful.
Top Symptoms: pain in one shoulder, spontaneous shoulder pain, pain that radiates down arm, pain in the back of the neck, severe shoulder pain
Urgency: Primary care doctor
Brachial plexopathy (shoulder nerve issue)
The brachial plexus is a web of nerves between the neck and shoulder, connecting the spinal cord nerves to the arm. There is one web on each side of the neck. Any injury that forces the shoulder to stretch down, and the neck to stretch up and away, can damage these nerves and cause brachial plexopathy.
Sports injuries and car accidents are often involved. Inflammation, tumors, and radiation treatment can also damage the brachial plexus.
Milder symptoms include numbness and weakness in the arm, with a shocklike stinging or burning sensation. A more severe injury can cause paralysis and loss of feeling in the arm, with pain in some parts of the arm, hand, and shoulder.
These symptoms should be seen by a medical provider since permanent damage can result if the injuries are not treated.
Diagnosis is made through electromyography (EMG) testing, CT scan, MRI, and sometimes angiogram.
Treatment usually involves rest and physical therapy. Surgery may be necessary to remove scar tissue or repair the damaged nerves.
Top Symptoms: pain in one arm, shoulder pain that shoots to the arm, arm weakness, numbness in one arm, shoulder pain
Symptoms that never occur with brachial plexopathy (shoulder nerve issue): pain in the front middle part of the neck
Urgency: Primary care doctor
Myasthenia gravis (over 50)
Myasthenia Gravis is an autoimmune disease, where the immune system attacks the connection between nerves and muscles.
Top Symptoms: weakness, general weakness, trouble swallowing, voice change, double vision
Urgency: In-person visit
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Questions your doctor may ask about weakness in both upper arms
- Do you have any idea what may have caused your upper arm pain?
- Have you ever been diagnosed with diabetes?
- Did you just suffer from a high impact injury (e.g., a fall, collision, accident or sports trauma)?
- Did you recently (within the last 2 weeks) get a vaccination?
Self-diagnose with our free Buoy Assistant if you answer yes on any of these questions.
Weakness in both upper arms symptom checker statistics
People who have experienced weakness in both upper arms have also experienced:
- 6% Fatigue
- 4% Shoulder Pain
- 4% Pain In The Upper Arm
People who have experienced weakness in both upper arms were most often matched with:
- 45% Myasthenia Gravis (Over 50)
- 27% Pinched Nerve In The Neck
- 27% Brachial Plexopathy (Shoulder Nerve Issue)
People who have experienced weakness in both upper arms had symptoms persist for:
- 39% Over a month
- 22% Less than a day
- 18% Less than a week
Source: Aggregated and anonymized results from Buoy Assistant.