Stuart Hershman, MD, is board-certified in orthopaedic surgery. He is the director of adult spinal deformity & complex spinal reconstruction at Massachusetts General Hospital and is on the faculty at Harvard Medical School.
Carpal tunnel syndrome is a condition in which compression of a nerve in the wrist—the median nerve—produces tingling, numbness, weakness, and pain in the hand and fingers. Early diagnosis is key to preventing permanent nerve damage and typically involves a physical examination, functional tests, and nerve conduction tests.
Treatment for carpal tunnel syndrome ranges from conservative approaches such as activity modification, nerve gliding exercises, icing, splints, and pain medication and cortisone injections. Some people find relief from yoga or acupuncture, but severe symptoms may require surgery.
Carpal tunnel syndrome occurs when the median nerve is pinched inside the wrist’s narrow carpal tunnel. There is usually no single cause that can be found for the condition. Instead, multiple risk factors often contribute, such as the structure of your wrist, injury, and the presence of conditions that cause inflammation and swelling. Stress due to repetitive motion is also a risk factor.
With carpal tunnel syndrome, you may feel pain, tingling, numbness, and weakness in your hand or fingers that prevents you from performing everyday activities, such as typing on a computer or writing. Some people also report a sensation like an electric shock. Symptoms develop gradually and worsen over time. Typically, these altered sensations correspond to the area the median nerve serves.
The median nerve, which is compressed in carpal tunnel syndrome, passes through your wrist to your palm, thumb, and each of your fingers except the pinky. The wrist’s carpal tunnel contains several tendons and vascular structures along with the median nerve.
Treatment of carpal tunnel syndrome usually begins with conservative treatments, such as using a wrist splint. Lifestyle changes and wrist stretches and exercises can also help. Corticosteroid injections or NSAIDs may be used to help reduce inflammation. If this does not provide relief or if your symptoms are severe, carpal tunnel release surgery is an option.
Over time, unaddressed carpal tunnel syndrome may cause you to lose grip strength or feeling in your fingers or hand. Eventually, your nerves may lose the ability to maintain a sense of where your hand is in space (known as proprioception1) and loss of strength, leading to clumsiness or inability to hold things. In the most severe cases, there is a risk of muscle atrophy and permanent nerve damage.
Entrapment neuropathy is a special category of compression injury. In this condition, irritation can cause ligaments, tendons, and muscles to become inflamed, constricting the narrow passageways through which nerves pass. These structures can place pressure on the nerve, causing symptoms. Carpal tunnel syndrome is the most common entrapment neuropathy of the arm.
The median nerve runs from the brachial plexus into the palm of the hand. The area where the forearm meets the wrist is called the carpal tunnel and contains several tendons and vascular structures along with the median nerve. The carpals are wrist bones, and they form the roof of the wrist’s tunnel. In carpal tunnel syndrome, the median nerve becomes pressed or squeezed at the wrist.
Tenosynovitis is inflammation of the synovium (a sheath that the tendon is housed in). Most of the time with tenosynovitis you also have tendonitis (inflammation of the tendon itself). It is common in the wrist but also specifically in the fingers and hand as well.
In a wrist flexion test (or Phalen test), you let the wrist fall forward into flexion and add pressure. If doing so causes numbness and tingling in the fingers within one minute, carpal tunnel syndrome is likely. The sooner such sensations appear during this test, the more severe your carpal tunnel syndrome is.
Explore an interactive model that shows an up-close view of the carpal tunnel, and how compression of the median nerve can cause symptoms throughout the hand.
Tapadia M, Mozaffar T, Gupta R. Compressive neuropathies of the upper extremity: update on pathophysiology, classification, and electrodiagnostic findings. J Hand Surg Am. 2010;35(4):668-77. doi:10.1016/j.jhsa.2010.01.007
Cleveland Clinic. Carpal tunnel syndrome: diagnosis and tests. Updated October 22, 2019.
American Academy of Orthopaedic Surgeons. Carpal tunnel syndrome—symptoms and treatment. OrthoInfo. Updated July 2016.
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