Diagnosing Carpal Tunnel Syndrome

To determine if you have carpal tunnel syndrome, NYU Langone specialists discuss your symptoms and medical history and perform a physical examination of your arm, hand, and wrist. They may also test for strength, sensation, and signs of nerve irritation or damage. Other tests used may include the following.

X-rays

During an X-ray, high-frequency beams of light are used to create pictures of the inside of the body. If you have limited wrist motion, an X-ray may be used to exclude other causes of wrist pain, such as arthritis, recent trauma, or past injuries.

MRI Scans

Your doctor may order an MRI, which uses a magnetic field and radio waves to create two- or three-dimensional pictures of the inside of the hand and wrist. This allows a better view of the median nerve.

Ultrasound

Your doctor may use ultrasound to evaluate the soft tissues of the carpal tunnel and the median nerve. During an ultrasound, high-frequency sound waves bounce off parts of the wrist and hand, capturing the returning “echoes” as images.

Electromyogram

Electrical testing of median nerve function can detect the presence, location, and extent of carpal tunnel syndrome and help your doctor to determine the most effective treatment. An electromyogram evaluates how the nerves and muscles work together by measuring the electrical impulse along nerves, nerve roots, and muscle tissue.

During this test, a technician inserts a tiny needle electrode through the skin and into the muscle. The electrode then measures the amount of electricity generated by muscle cells when they become activated by nearby nerves.

The results of the electromyogram can help doctors to distinguish between conditions that begin in the muscle and nerve disorders that cause muscle weakness, such as carpal tunnel syndrome.

Nerve Conduction Study

If your hand or wrist feels numb or tingly, your doctor may order a nerve conduction study, which can determine if there is any nerve damage by measuring how fast an electrical impulse travels through a nerve.

Nerves can be thought of as electrical cables that carry messages between your brain and muscles. When a nerve is not working well, it takes too long to conduct those signals. During a nerve conduction test, the nerve is stimulated, and the time it takes to respond is measured. Several places along the nerve are tested, and the area where the response takes too long is likely to be the place where the nerve is compressed. The presence of carpal tunnel syndrome can be indicated by slower electrical responses in the carpal tunnel.

NYU Langone’s doctors use the results of these diagnostic tests to create a treatment plan tailored to your needs.