A reflex hammer is a medical instrument used by practitioners to test deep tendon reflexes. Testing for reflexes is an important part of the neurological physical examination in order to detect abnormalities in the central or peripheral nervous system. Reflex hammers can also be used for chest

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.Swartz MH. ''Textbook of Physical Diagnosis: History and Examination.'' Third edition. Philadelphia: WB Saunders; 1998

Models of reflex hammer

Prior to the development of specialized reflex hammers, hammers specific for percussion of the chest were used to elicit reflexes.Lanska DJ. The history of reflex hammers. ''Neurology''. 1989 Nov;39(11):1542-9. However, this proved to be cumbersome, as the weight of the chest percussion hammer was insufficient to generate an adequate stimulus for a reflex. Starting in the late 19th century, several models of specific reflex hammers were created: *The Taylor or tomahawk reflex hammer was designed by John Madison Taylor in 1888 and is the most well known reflex hammer in the USA. It consists of a triangular

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component which is attached to a flat metallic handle. The traditional Taylor hammer is significantly lighter in weight when compared to the heavier European hammers. *The Queen Square reflex hammer was designed for use at the ''National Hospital for Nervous Diseases'' (now the National Hospital for Neurology and Neurosurgery) in Queen Square, London. It was originally made with a

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or cane handle of varying length, of average 10 to 16 inches (25 to 40 centimetres), attached to a 2-inch (5 centimetre) metal disk with a plastic bumper. The Queen Square hammer is also now made with plastic molds, and often has a sharp tapered end to allow for testing of plantar reflexes though this is no longer recommended due to tightened infection control. It is the reflex hammer of choice of the UK neurologist. *The Babinski reflex hammer was designed by

Joseph Babiński Joseph Jules François Félix Babinski ( pl, Józef Julian Franciszek Feliks Babiński; 17 November 1857 – 29 October 1932) was a France, French-Poland, Polish professor of neurology. He is best known for his 1896 description of the Babinski sig ...

in 1912 and is similar to the Queen Square hammer, except that it has a metallic handle that is often detachable. Babinski hammers can also be telescoping, allowing for compact storage. Babinski's hammer was popularized in clinical use in America by the neurologist Abraham Rabiner, who was given the instrument as a peace offering by Babinski after the two brawled at a black tie affair in

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. *The Trömner reflex hammer was designed by Ernst Trömner. This model is shaped like a two-headed mallet. The larger mallet is used to elicit tendon stretch reflexes, and the smaller mallet is used to elicit percussion myotonia. *Other reflex hammer types include the Buck, Berliner and Stookey reflex hammers. There are numerous models available from various commercial sources.

Method of use

The strength of a reflex is used to gauge central and peripheral nervous system disorders, with the former resulting in hyperreflexia, or exaggerated reflexes, and the latter resulting in hyporeflexia or diminished reflexes. However, the strength of the stimulus used to extract the reflex also affects the magnitude of the reflex. Attempts have been made to determine the force required to elicit a reflex, but vary depending on the hammer used, and are difficult to quantify. The Taylor hammer is usually held at the end by the physician, and the entire device is swung in an arc-like motion onto the tendon in question. The Queen Square and Babinski hammers are usually held

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to the tendon in question, and are passively swung with

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assistance onto the tendon. The

Jendrassik maneuver The Jendrassik maneuver is a medical maneuver wherein the patient clenches the teeth, flexes both sets of fingers into a hook-like form, and interlocks those sets of fingers together. The tendon below the patient's knee is then hit with a ref ...

, which entails interlocking of flexed

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s to distract a patient and prime the reflex response, can also be used to accentuate reflexes.Delwaide PJ, Toulouse P. The Jendrassik maneuver: quantitative analysis of reflex reinforcement by remote voluntary muscle contraction. ''Adv Neurol.'' 1983;39:661-9. In cases of hyperreflexia, the physician may place his finger on top of the tendon, and tap the finger with the hammer. Sometimes a reflex hammer may not be necessary to elicit hyperreflexia, with finger tapping over the tendon being sufficient as a stimulus.

References

{{Medical instruments and implants , state=expanded Neurology Hammers Medical equipment 1888 introductions

Models of reflex hammer

Method of use

See also

References