What is a finger flexor reflex?
An involuntary contraction of finger flexors in response to sudden stretching. To test for it, tap gently
on the palm (or on the distal phalanxes of the index and middle fingers) with your reflex hammer.
Alternatively, hold the patient’s middle finger between your thumb and index finger, with the other fingers as
relaxed as possible. Then, press with your thumbnail on the patient’s nail, moving it down until your nail
“clicks” over the edge of the patient’s nail. This “click” should elicit no response in normal subjects. In patients with upper motor neuron disease, it will cause instead transient flexion of the other fingers (positive
Hoffmann’s sign). In other words, flicking (or nipping) the nail of the second, third, or fourth finger will cause all fingers (and possibly the thumb) to flex. The maneuver is then repeated for the other hand.
Hoffmann’s is a sign of hyperreflexia. Hence, it indicates upper motor neuron disease of the upper extremities—typically Werdnig-Hoffmann syndrome.
Basically, Hoffmann’s is to the upper extremities what Babinski is to the lower extremities: a sign of upper motor neuron disease. The sign is linked to the German neurologist Johan Hoffmann (1857–1919), who studied and taught at Heidelberg. Although he discussed the reflex in his teaching (and used it in practice), he never actually wrote it up. This was eventually done by one of his students (Hans Curschmann), who credited his mentor, so that the sign came to be known as Hoffmann’s reflex.
An involuntary contraction of finger flexors in response to sudden stretching. To test for it, tap gently
on the palm (or on the distal phalanxes of the index and middle fingers) with your reflex hammer.
Alternatively, hold the patient’s middle finger between your thumb and index finger, with the other fingers as
relaxed as possible. Then, press with your thumbnail on the patient’s nail, moving it down until your nail
“clicks” over the edge of the patient’s nail. This “click” should elicit no response in normal subjects. In patients with upper motor neuron disease, it will cause instead transient flexion of the other fingers (positive
Hoffmann’s sign). In other words, flicking (or nipping) the nail of the second, third, or fourth finger will cause all fingers (and possibly the thumb) to flex. The maneuver is then repeated for the other hand.
Hoffmann’s is a sign of hyperreflexia. Hence, it indicates upper motor neuron disease of the upper extremities—typically Werdnig-Hoffmann syndrome.
Basically, Hoffmann’s is to the upper extremities what Babinski is to the lower extremities: a sign of upper motor neuron disease. The sign is linked to the German neurologist Johan Hoffmann (1857–1919), who studied and taught at Heidelberg. Although he discussed the reflex in his teaching (and used it in practice), he never actually wrote it up. This was eventually done by one of his students (Hans Curschmann), who credited his mentor, so that the sign came to be known as Hoffmann’s reflex.