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Left Arm Numbness – 6 Causes You Need to Know!

left arm numbness

Over the last several days you noticed that you have left arm numbness.  Your mind is wildly looking for answers.  What causes it? When should you be concerned about it?  What are the treatment options?  Let’s dig in.

Sitting or lying on the couch too long while watching a game or series can cause left arm numbness which promptly resolves with movement.  This is typically caused by restricted blood flow or excessive pressure on a nerve.  If numbness in the arm is abrupt in onset or persists, this is a warning sign!

What Causes Left Arm Numbness?

Left-arm numbness can be frightening.  There are many causes, and the major ones include:

1. Thoracic Outlet Syndrome

Thoracic outlet syndrome is a group of disorders that involve the compression and irritation of the nerves, arteries, and veins in the lower neck and chest (1).  Pain is a major symptom and can be intermittent or constant and varies in severity and quality.  The pain can involve the lower neck, collar bone, and hand.   Left-arm numbness can also be present.

2. Cervical Nerve Irritation

The neck is composed of seven building blocks called vertebral bodies.  Sandwiched between each of the building blocks is a disc.  They are important shock absorbers in the neck.   Nerves exit the spine at each level sending important information to the arm and hand.  Unfortunately, cervical discs can be injured by trauma, degeneration, infection, and arthritis (2).  Common cervical disc injuries are bulges or herniations both of which can cause cervical nerve irritation or compression.  This compression can result in a number of symptoms which include left arm numbness.

3. Cervical Stenosis

The spinal cord extends from the brain down to the low back.  It is enclosed in the spinal canal which contains spinal fluid and the spinal cord.  If the spinal canal becomes narrowed the spinal cord can become irritated or compressed.  This compression is called stenosis and causes a number of symptoms including left arm numbness (3).  To learn more about cervical stenosis please click in the video below.


A heart attack occurs when there are insufficient blood flow and oxygen to the heart.  This can occur as a result of reduced or blocked blood flow due to a blood clot or plaque.   A heart attack is a serious medical emergency.  Symptoms include chest discomfort, lightheadedness, nausea, and shortness of breath.  Patients may have arm pain or numbness.  If you or somebody with you has these symptoms immediate evaluation is required. CALL 911 immediately.


A stroke occurs when there is an interruption of blood flow to the brain (4).  There are two major types of strokes:  ischemic and hemorrhagic.  In an ischemic stroke,  blood clots or fatty deposits within the blood vessel restrict blood flow to the brain.  In a hemorrhagic stroke, one or more blood vessels rupture.  In both cases, there is impaired brain blood flow.  Brain cells start dying.  Symptoms vary in character and intensity.

FAST is an important acronym to help detect and enhance responsiveness to the needs of a person having a stroke

Facial Drooping

Arm weakness or numbness

Speech difficulties

Time.  If any of the above symptoms are present time is critical. CALL 911

6. Nerve Injury

Nerves pass through muscles, tendons, ligaments, and boney surfaces and they coarse through the arm to the hand. They are susceptible to compression, irritation, or injury at multiple points.  Symptoms include pain tingling, weakness, and arm numbness.  Common sites of compression include the elbow and wrist. Common peripheral nerve injuries include:

Carpal Tunnel Syndrome: Numbness and tingling in the hand and arm due to compression of the median nerve at the level of the wrist.  It is the most common peripheral nerve compression condition in the upper arm.  It is a condition of middle-aged individuals and affects females more often than males (5)

Cubital Tunnel Syndrome:  involves compression of the ulnar nerve at the level of the elbow.  Symptoms include forearm pain, weakness n the hand, and numbness and tingling in the ring and fifth finger. Cubital tunnel syndrome is the second most common peripheral nerve entrapment neuropathy in the upper limb (6).  Risk factors for cubital tunnel syndrome include diabetes, obesity, trauma, and holding a tool for prolonged periods with elbow bent (7).

When Should I be Concerned 

Unexplained arm numbness requires immediate attention.  If left arm numbness is abrupt in onset and not due to trauma or compromised posture time is of the essence.  Call 911!

Treatment Options for Left Arm Numbness

Treatment depends upon the underlying cause of the arm numbness.  Left-arm numbness is a warning sign that requires attention.  As noted above unexplained numbness requires immediate attention.

At the Centeno-Schultz Clinic, we are experts in the treatment of left-arm numbness due to cervical nerve irritation, cervical stenosis, thoracic outlet syndrome, and peripheral nerve injuries. When appropriate first-line treatment should involve conservative care including physical therapy and stretching. Steroid injections should be avoided as they are toxic to orthopedic tissue and can accelerate damage (8)

Surgery for Cervical Stenosis and Thoracic Outlet Syndrome is major surgery and associated with significant risks.  These risks include infection, nerve damage, failure to fuse, and Adjacent Segment Disease.  A previous blog details the risks and nonsurgical treatment options for Cervical Stenosis.

Treatment options include stem cells and platelets. At the Centeno-Schultz Clinic, there are different PRP treatment options for different conditions.  Platelet lysate is ideal for the treatment of nerve injuries.  It super concentrates growth factors found in platelets.  To learn more about platelet lysate and growth factors please click on the video below.

In Conclusion

Left-arm numbness can be alarming.  The major causes include Thoracic Outlet Syndrome, cervical nerve injury, Cervical Stenosis, heart attack, stroke, and nerve injury.  Unexplained left arm numbness requires immediate attention.  Treatment options depend upon the underlying cause.  The Centeno-Schultz Clinic Physicians are experts in the non-surgical treatment of left arm numbness due to thoracic outlet syndrome, cervical stenosis, cervical nerve injury, and peripheral nerve compression.  Treatment options include PRP and stem cells.  Left-arm numbness is a warning signal that requires attention.  If abrupt in onset and not due to trauma or compromised posture time is of the essence.

If you are or a loved one is suffering from progressive left arm numbness due to cervical, thoracic injuries or peripheral nerve compression, please contact us.   Schedule a Telemedicine consult with a board-certified physician who can review your history, studies, and provide you the best nonsurgical treatment option.  Listen to your body as it is warning you!


1.Jones MR, Prabhakar A, Viswanath O, et al. Thoracic Outlet Syndrome: A Comprehensive Review of Pathophysiology, Diagnosis, and Treatment. Pain Ther. 2019;8(1):5-18. doi:10.1007/s40122-019-0124-2

2..Peng B, DePalma MJ. Cervical disc degeneration and neck pain. J Pain Res. 2018;11:2853-2857. Published 2018 Nov 14. doi:10.2147/JPR.S180018

3.Meyer F, Börm W, Thomé C. Degenerative cervical spinal stenosis: current strategies in diagnosis and treatment. Dtsch Arztebl Int. 2008;105(20):366-372. doi:10.3238/arztebl.2008.0366

4.French BR, Boddepalli RS, Govindarajan R. Acute Ischemic Stroke: Current Status and Future Directions. Mo Med. 2016;113(6):480-486.

5.Aroori S, Spence RA. Carpal tunnel syndrome. Ulster Med J. 2008;77(1):6-17.

6.Cutts S. Cubital tunnel syndrome. Postgrad Med J. 2007;83(975):28-31. doi:10.1136/pgmj.2006.047456.

7. Descatha A, Leclerc A, Chastang JF, Roquelaure Y; Study Group on Repetitive Work. Incidence of ulnar nerve entrapment at the elbow in repetitive work. Scand J Work Environ Health. 2004;30(3):234-240. doi:10.5271/sjweh.784.

8. Wernecke C, Braun HJ, Dragoo JL. The Effect of Intra-articular Corticosteroids on Articular Cartilage: A Systematic Review. Orthop J Sports Med. 2015;3(5):2325967115581163. Published 2015 Apr 27. doi:10.1177/2325967115581163

Learn more about your elbow condition and how Interventional Orthopedics can prevent the need for surgery by reading Orthopedics 2.0.