In medicine, Hoffmann's reflex, named after the German neurologist, Johann Hoffmann (born 1857, Rheinhesse; died 1919, Heidelberg),[1] is a finding elicited by a reflex test which verifies the presence or absence of problems in the corticospinal tract. It is also known as the finger flexor reflex.
The test involves tapping the nail or flicking the terminal phalanx of the middle or ring finger. A positive response is seen with flexion of the terminal phalanx of the thumb.
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Hoffmann's reflex is often considered the upper limb equivalent of the Babinski's sign[2] because it, like the Babinski sign, indicates upper motor neuron dysfunction.[3] Its mechanism differs considerably from the Babinski; Hoffmann's reflex involves a monosynaptic reflex pathway in Rexed lamina IX of the spinal cord, normally fully inhibited by descending input. The pathways involved in the plantar reflex are more complicated, and different sorts of lesions may interrupt them. This fact has led some neurologists to reject strongly any analogies between the finger flexor reflex and the plantar response. When both lower and upper neuron damage is indicated, it leads a physician to indicate a motor neuron illness, such as amyotrophic lateral sclerosis.
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