Hoffmann's reflex

In medicine, Hoffmann's reflex, named after Johann Hoffmann, 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 Hoffman reflex has also been used as a measure of spinal reflex processing (adaptation) in response to exercise training.

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.

Hoffmann's reflex is often erroneously called 'the Babinski's sign of the upper limb'. However the two reflexes are quite different, and should not be equated with each other.

A positive Babinski sign is considered a pathological sign of upper motor neuron disease except for infants, in whom it is normal. Whereas, a positive Hoffmann's sign can be present in an entirely normal patient. A positive Hoffman's sign in the normal patients is more commonly found in those who are naturally hyper-reflexive (e.g. 3+ reflexes). A positive Hoffmann's sign is a worrisome finding of a disease process if its presence is asymmetrical, or has an acute onset.

Another significant difference between Hoffmann's reflex and the Babinski sign are their mechanism of reflex. Hoffman's reflex is a deep tendon reflex (spindle fibre) with a monosynaptic reflex pathway in Rexed lamina IX of the spinal cord. On the other hand, the plantar reflex is not a deep tendon reflex, and its pathway is both more complicated and not fully understood.

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