Tinel’s Test is a standard, non-invasive physical examination technique used by medical professionals, especially in orthopedics and neurology, to evaluate the health of peripheral nerves. It is a rapid way to screen for nerve irritation or compression, often serving as a preliminary diagnostic tool when a patient reports symptoms like numbness or tingling.
Purpose and Underlying Mechanism
The primary goal of Tinel’s Test is to locate a specific point of irritation, compression, or regeneration in a peripheral nerve. When these nerves are damaged or compressed, the axons become hypersensitive to mechanical stimulation. The test relies on the physiological principle that a mechanical tap over a compromised segment triggers an abnormal electrical impulse. This impulse travels along the nerve’s pathway, resulting in a distinctive tingling or “pins and needles” feeling, known as paresthesia, distributed to the area the nerve supplies. This hypersensitivity is also present in a nerve that is actively regenerating after an injury, making the test useful for monitoring recovery.
Performing the Examination
The procedure for Tinel’s Test is straightforward, requiring minimal equipment, usually just a fingertip or a reflex hammer. The patient is positioned comfortably while the clinician identifies the suspected course of the affected nerve, such as the median nerve at the wrist crease. The clinician then applies light percussion directly over the nerve pathway. The tapping is a series of gentle strikes, often starting distal to the suspected injury and moving proximally, or directly over the site of potential compression. The patient is asked to report any sensations they feel during the tapping.
Interpreting the Response
A positive result, known as Tinel’s sign, occurs if the patient experiences paresthesia that radiates distally along the nerve’s distribution. The location where the tingling is most strongly felt directly pinpoints the site of nerve irritation or entrapment. This sign supports the diagnosis of various entrapment neuropathies, such as Carpal Tunnel Syndrome (median nerve at the wrist) and Cubital Tunnel Syndrome (ulnar nerve at the elbow). It is also used for Tarsal Tunnel Syndrome, affecting the posterior tibial nerve. A negative result means the patient feels no radiating tingling sensation, though a compressed nerve can still be present, requiring further diagnostic measures.