What Causes Numbness in One Upper Arm & When to Seek Care
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Numbness in the left arm or right arm can be caused from trauma from an injury, compressed nerves or overuse of the upper arm muscles. Other causes of upper arm numbness and tingling include a pinched nerves within the neck or a mini stroke. Read below for more information and how to find relief for an upper arm going numb.
Symptoms of numbness in one upper arm
Numbness in one upper arm can be described as a loss of sensation or tingling. Not being able to completely feel the upper arm or move it properly despite stimulus can understandably cause feelings of nervousness or discomfort. Causes can be related to injury or underlying medical conditions that can be properly identified by your medical provider.
Common characteristics of numbness in one upper arm
For example, symptoms you may also experience that accompany your upper arm numbness can include:
- Pins and needles sensation
- Sensitivity to touch
It is important to follow-up with your physician if you are experiencing any of the above symptoms. Numbness in your upper arm can have a variety of different causes and may require prompt treatment.
Nerves in the upper arm
The upper arm is controlled by a complicated branching system of nerves called the brachial plexus . This plexus of nerves start from the cervical spinal cord, travels down the neck, over the first rib, and into the armpit to provide innervation to not only the arm and hand but also the chest and shoulder. See an image of the brachial plexus here and here.
Sensation (also called cutaneous innervation) of the upper arm is primarily controlled by a branch of the brachial plexus called the axillary nerve. Part of the area over the shoulders is also controlled by supraclavicular nerves; however, these nerves are not part of the brachial plexus but also branch from the cervical spinal cord. See an image of this innervation relationship here.
Causes of numbness in one upper arm
Upper arm numbness is the result of injury, compression or irritation primarily of the axillary nerve. Symptoms can also be caused by other nerves in that area. Thus, causes that result in upper arm numbness are varied but can be divided into the following categories.
Traumatic causes of numbness in one upper arm may be related to the following.
- Direct injury: Direct injury to the muscles and bones of the upper arm in the form of dislocations, fractures, and even sprains can also result in injury to the nerves of the upper arm resulting in numbness, tingling, and pain.
- Compressive injury: Surprisingly, the axillary nerve is very susceptible to compression from non-traumatic causes. For example, compression of the brachial plexus, and in turn, the axillary nerve by anatomical structures in the area (such as the first rib or clavicle) can result in a variety of symptoms including numbness of the upper arm. This is known as thoracic outlet syndrome.
- Entrapment: The axillary nerve may become trapped in rare cases. The space it runs through, called the quadrilateral space, is framed by the teres minor muscle at the top, the humerus bone on one side, the long head of the triceps muscle on the other side, and the teres major muscle at the bottom. See an image of this space and its relationship to the axillary nerve here.
Causes related to systemic disease may include the following.
- Metabolic: Dysfunction in the processes that your body uses day-to-day, for example, glucose and insulin dysregulation in diabetes, can damage the peripheral nerves causing numbness in one upper arm and other parts of the body (this condition is known as peripheral neuropathy).
- Tumors: Cancerous and noncancerous growths in the body can directly grow and compress nerves in the upper arm, including the axillary nerve. However, this is considered rare.
This list does not constitute medical advice and may not accurately represent what you have.
Repetitive strain injury of the upper arm
Repetitive strain injury of the upper arm is caused by consistent repetitive use.
Top Symptoms: upper arm pain from overuse, upper arm weakness, upper arm numbness
Symptoms that always occur with repetitive strain injury of the upper arm: upper arm pain from overuse
Symptoms that never occur with repetitive strain injury of the upper arm: upper arm injury, severe upper arm pain
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
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
Stroke or tia (transient ischemic attack)
Transient ischemic attack, or TIA, is sometimes called a "mini stroke" or a "warning stroke." Any stroke means that blood flow somewhere in the brain has been blocked by a clot.
Risk factors include smoking, obesity, and cardiovascular disease, though anyone can experience a TIA.
Symptoms are "transient," meaning they come and go within minutes because the clot dissolves or moves on its own. Stroke symptoms include weakness, numbness, and paralysis on one side of the face and/or body; slurred speech; abnormal vision; and sudden, severe headache.
A TIA does not cause permanent damage because it is over quickly. However, the patient must get treatment because a TIA is a warning that a more damaging stroke is likely to occur. Take the patient to the emergency room or call 9-1-1.
Diagnosis is made through patient history; physical examination; CT scan or MRI; and electrocardiogram.
Treatment includes anticoagulant medication to prevent further clots. Surgery to clear some of the arteries may also be recommended.
Top Symptoms: dizziness, leg numbness, arm numbness, new headache, stiff neck
Symptoms that never occur with stroke or tia (transient ischemic attack): bilateral weakness
Urgency: Emergency medical service
Herniated (slipped) disk in the upper back
The backbone, or spine, is made up of 26 bones called vertebrae. In between the bones are soft disks filled with a jelly-like substance. These disks cushion the vertebrae and keep them in place. Although people talk about a slipped disk, nothing actually slips out of place. The outer shell of the disk ruptures, and the jelly-like substance bulges out. It may be pressing on a nerve, which is what causes the pain.A slipped disk is more likely to happen due to strain on the back, such as during heavy lifting, and older individuals are at higher risk.
Top Symptoms: upper back pain, neck pain, arm weakness, back pain that gets worse when sitting, upper spine pain
Symptoms that always occur with herniated (slipped) disk in the upper back: upper back pain
Urgency: Primary care doctor
Chemotherapy-induced nerve damage
Chemotherapy has many effects on the body. Some types of chemotherapy can cause irritation of the nerves in ones hands and feet, resulting in symptoms like pain, numbness or tingling.
Top Symptoms: muscle aches, distal numbness, pain in both hands, pain in both feet, numbness
Urgency: Primary care doctor
Multiple sclerosis (ms)
Multiple sclerosis, or MS, is a disease of the central nervous system. The body's immune system attacks nerve fibers and their myelin covering. This causes irreversible scarring called "sclerosis," which interferes with the transmission of signals between the brain and the body.
The cause is unknown. It may be connected to a genetic predisposition. The disease usually appears between ages 20 to 50 and is far more common in women than in men. Other risk factors include family history; viral infections such as Epstein-Barr; having other autoimmune diseases; and smoking.
Symptoms include numbness or weakness in arms, legs, or body; partial or total loss of vision in one or both eyes; tingling or shock-like sensation, especially in the neck; tremor; and loss of coordination.
Diagnosis is made through patient history, neurological examination, blood tests, MRI, and sometimes a spinal tap.
There is no cure for MS, but treatment with corticosteroids and plasma exchange (plasmapheresis) can slow the course of the disease and manage symptoms for better quality of life.
Top Symptoms: severe fatigue, constipation, numbness, decreased sex drive, signs of optic neuritis
Urgency: Primary care doctor
B12 is an essential vitamin for the production of myelin, a compound that speeds up the conduction of nerve impulses, and the production of red blood cells, the cells that carry oxygen throughout the body. It only occurs naturally in diets containing animal byproducts.
Numbness in one upper arm treatments and relief
You can likely prevent temporary numbness with the following lifestyle changes.
- Be mindful of sleeping positions: Sleeping on your back with your arms above your head can temporarily compress the axillary nerve, resulting in your arm "falling asleep." Try to be aware of how you sleep and make yourself as comfortable as possible.
- Avoid repetitive motions or cramped positions: This could lead to numbness if unnecessary pressure is put on your shoulders.
- Other tips: Relief can be found by improving your posture, buying support for your back while typing, or taking breaks throughout the day in order to lessen compression and irritation of the nerves in your arms/shoulders.
When to see a doctor for further treatment
If you experience frequent, persistent episodes of numbness, visit your physician to get appropriate treatment. Depending on the cause, your physician may first suggest other lifestyle modifications such as:
- Regular exercise: Maintaining an optimal weight with exercise as well as a balanced diet can prevent and also control metabolic diseases such as obesity and diabetes.
- Medications: Your physician may be able to give you a prescription that can treat tingling and other symptoms related to numbness in the upper shoulder.
- Physical therapy: If your shoulder numbness is due to compression of the nerves and blood vessels leading to your arm and hand, your physician may suggest therapy to help take the pressure off of these body parts, which also may improve your range of motion and posture.
- Surgery: If other treatments are ineffective and your symptoms continue to progress or worsen, your physician may recommend looking into surgical options.
When it is an emergency
If you experience any symptoms of speech difficulty, facial drooping, or weakness to the point you cannot raise your arm, call 911 immediately. These could be signs of a stroke.
FAQs about numbness in one upper arm
Will the numbness in my upper arm affect how I use my arm/hand?
The numbness in your upper arm may be associated with problems moving the arm and hand. The axillary nerve is both a motor and sensory nerve, so it allows both movement and sensation. You may have some difficulty rotating or abducting the shoulder, but since there are other muscles that help with these movements, it should not be severe. If compression or injury of the brachial plexus results in injury to other nerves, you may also experience difficulties moving the hand.
Why am I only feeling numbness in one arm?
You are only feeling numbness in one upper arm because the nerve in that specific arm has been affected — the nerve in the other arm has not.
Is numbness in one upper arm life-threatening?
Usually, numbness in one upper arm is not life-threatening, especially if it is related to compression. Compartment syndrome is a life- and or limb-threatening condition in which increased pressure within a confined space can restrict blood flow to an organ. You may experience numbness, but usually, compartment syndrome is associated with severe trauma and symptoms such as paralysis, lack of pulse, and changes in the color of the extremity. This condition requires immediate medical attention.
Will the numbness spread from my upper arm to other parts of my arm or upper body?
If your symptoms are due to compression of the axillary nerve via the brachial plexus, your symptoms may spread to other parts of the arm and hand depending on which other branches and nerves of the plexus are affected.
How long will the numbness last?
Decompression of the axillary nerve usually results in very fast relief in cases not related to trauma. Decompression in this context can be achieved by simply moving the arm to a more comfortable position or "shaking" it out.
Questions your doctor may ask about numbness in one upper arm
- Have you been experiencing any muscle weakness that is symmetrical (equal on both sides of your body)?
- Are you having any difficulty speaking?
- Have you lost some or all of your sense of taste?
- Do food or drinks get stuck when you swallow?
Self-diagnose with our free Buoy Assistant if you answer yes on any of these questions.
Dr. Gambrah-Lyles is a resident pediatrician at the Children's Hospital of Philadelphia. She is a graduate of the University of Pennsylvania Perelman School of Medicine (2019). She graduated cum laude and received her undergraduate degree in Biochemistry and Spanish from Washington University in St. Louis (2013). Her research explores the intersections between neurology, public health, and infectious disease. She has investigated nutrition and cerebral palsy in Botswana, and completed a year-long project in Brazil, researching growth and developmental outcomes of Zika virus infection in pediatric patients as a Doris Duke International Scholar. Dr. Gambrah-Lyles speaks four languages, loves staying active, and enjoys sharing her love for medicine through teaching and writing.
- Numbness and tingling. Massachusetts General Hospital Orthopaedics. Mass General Link
- Peripheral nerve injury in the upper extremity. University of Michigan: Michigan Medicine. UMichigan Medicine Link
- Thoracic outlet syndrome. University of Rochester Medical Center. URMC Link
- Peripheral nerve disorders. U.S. National Library of Medicine: MedlinePlus. Updated October 23, 2018. MedlinePlus Link
- Neal SL, Fields KB. Peripheral nerve entrapment and injury in the upper extremity. American Family Physician. 2010;81(2):147-155. AAFP Link
- Brachial plexus injuries. American Academy of Orthopedic Surgeons: OrthoInfo. Reviewed June 2015. OrthoInfo Link
- Thoracic outlet syndrome information page. National Institute of Neurological Disorders and Stroke. Updated June 18, 2018. NINDS Link