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.
9 most common cause(s)
5 causes of weakness in both upper arms
This list does not constitute medical advice and may not accurately represent what you have.
Thoracic outlet syndrome
The "thoracic outlet" is the space on either side of the base of the neck where nerves, arteries, and veins travel beneath the collarbone. If these become compressed or damaged, the condition is called thoracic outlet syndrome or TOS.
The most common causes are trauma, such as a car accident or fall; and repetition or overuse, such as a sports injury.
Symptoms vary depending on the structures being compressed:
- Neurogenic TOS affects the nerves. It is the most common form and creates numbness, tingling, pain, and weakness in the arms, hand, and fingers.
- Vascular TOS affects the arteries and veins. It creates the same symptoms as neurogenic TOS as well as cold, pale hands and arms with weak pulse.
It is important to see a medical provider about these symptoms so that the damage does not become permanent.
Diagnosis is made through patient history, physical examination, imaging such as x-ray or ultrasound, and sometimes nerve conduction and blood flow studies.
Treatment involves physical therapy, pain relievers, and sometimes surgery.
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.
Rarity: Common
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
Limb-girdle muscular dystrophy
Limb-girdle muscular dystrophy is an inherited disorder that involves varying muscle weakness and wasting.
You should visit your primary care physician to confirm the diagnosis and discuss treatment options for managing symptoms.
Idiopathic inflammatory myopathy
Idiopathic inflammatory myopathy refers to a closely related group of conditions that cause inflammation of muscle tissue.
Make an appointment with a physician to determine exactly what subtype of inflammatory myopathy you are experiencing. The physician will most likely prescribe a oral steroid to reduce inflammation and put in an IV to protect the kidneys.
Hyperparathyroidism
The four parathyroids are tiny glands that lie behind the thyroid gland in the neck and control calcium levels in the blood and bones.
In most cases, enlargement of one or more of the parathyroids causes overproduction of parathyroid hormone (PTH.) This is followed by hypercalcemia, or high blood calcium levels.
Sometimes a benign or malignant tumor on one of the parathyroids is the cause. Other causes are chronic kidney failure or a deficiency of calcium and/or vitamin D.
Most at risk are women past menopause with a pre-existing calcium deficiency; radiation treatment to the neck; or use of the drug lithium.
Early symptoms are those of hypercalcemia: brittle bones, excessive urination, tiring easily, depression, and generally feeling ill with no clear cause.
If not treated, hyparathyroidism can lead to osteoporosis, kidney stones, and cardiovascular disease.
Diagnosis is made through blood test. Bone mineral tests, urine tests, and imaging of the kidneys may be ordered.
Treatment includes monitoring; medications called calcimimetics or bisphosphonates; and surgery to remove the affected parathyroid glands.
Guillain-barre syndrome
Guillain-Barre syndrome is an autoimmune condition triggered by infection. It causes damage to nerves in the body that control muscles. This leads to weakness, usually starting in the legs and then progressing to the arms.
Patients with Guillain-Barre syndrome should seek immediate medical care at an ER. Nerve damage can potentially impair your ability to control your heart and lungs. You may need to be admitted to the hospital.
Cushing syndrome
Cushing syndrome is a hormonal disorder that occurs when there is too much of the stress hormone cortisol in the body. It can be caused by taking steroid medications commonly prescribed for asthma or arthritis, or by problems with the glands in the body that are involved in creating cortisol. Symptoms can vary from person to person but often include easy bruising, a "hump" on the back, and stretch marks. Fatigue, large stomach, red round face, and high blood sugar may also occur.
You should consider visiting a medical professional in the next week or two to discuss your symptoms. Cushing syndrome can be evaluated with a review of your symptoms and medical history, as well as blood tests. Treatment depends on the cause of your condition. If caused by steroid medication, you may be instructed to lower the dosage slowly over time. If caused by issues with your glands, surgery, radiation, or medication may be an option.
Brachial plexopathy (shoulder nerve issue)
A shoulder nerve injury, also called brachial plexopathy, is when damage occurs to a network of nerves in the front of the shoulder known as the brachial plexus. This damage can occur from injury, inflammation, radiation therapy, or other medical conditions. Symptoms include sharp pain in the shoulder, arm, or hand. Numbness or weakness in the shoulder or arm may also occur.
You should consider visiting a medical professional to discuss your symptoms. A doctor can evaluate shoulder nerve issues with a review of your symptoms and medical history. You might also be asked to do an EMG, a test that checks the connection between muscles and nerves. Once diagnosed, some options for treatment include pain or nerve block medication, physical therapy, and braces or splints. Some cases may require surgery. Depending on the severity, recovery times can range from weeks to years.
Rarity: Uncommon
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
Amyotrophic lateral sclerosis (ALS)
Amyotrophic lateral sclerosis is also called ALS or Lou Gehrig's Disease. It is a degenerative disease that destroys nerve cells, which eventually leads to loss of control over muscle function.
The cause of ALS is not known. It may be inherited and/or due to a chemical imbalance, faulty autoimmune response, or exposure to toxic environmental agents.
Symptoms include weakness; difficulty with speaking, swallowing, walking, or using the hands; and muscle cramps. The muscles of the arms, hands, legs, and feet are most involved at first. It does not affect the senses or a person's mental ability.
ALS is progressive, meaning it worsens over time. There is no cure, but supportive care can keep the patient comfortable and improve quality of life.
Diagnosis is made through several tests including blood tests; urine tests; MRI; electromyography (EMG) to measure muscle activity; nerve conduction studies; and sometimes muscle biopsy or spinal tap (lumbar puncture.)
Treatment involves medications to both slow the progression of the disease and ease the symptoms; respiratory therapy; physical therapy; occupational therapy; and psychological support.
Myasthenia gravis (over 50)
Myasthenia Gravis is an autoimmune disease, where the immune system attacks the connection between nerves and muscles.
Rarity: Rare
Top Symptoms: weakness, general weakness, trouble swallowing, voice change, double vision
Urgency: In-person visit
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.
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