Hoffmann's reflex (Hoffmann's sign, sometimes simply "''Hoffmann's''", also finger flexor reflex) is a neurological examination finding elicited by a

reflex test In biology, a reflex, or reflex action, is an involuntary, unplanned sequence or action and nearly instantaneous response to a stimulus. Reflexes are found with varying levels of complexity in organisms with a nervous system. A reflex occurs ...

which can help verify the presence or absence of issues arising from the

corticospinal tract The corticospinal tract is a white matter motor pathway starting at the cerebral cortex that terminates on lower motor neurons and interneurons in the spinal cord, controlling movements of the limbs and trunk. There are more than one million neur ...

. It is named after neurologist Johann Hoffmann. Usually considered a pathological reflex in a clinical setting, the Hoffmann's reflex has also been used as a measure of spinal reflex processing (adaptation) in response to exercise training.

Procedure

The Hoffmann's reflex test itself involves loosely holding the middle finger and flicking the fingernail downward, allowing the middle finger to flick upward reflexively. A positive response is seen when there is flexion and adduction of the thumb on the same hand. Hoffman reflex - A complete guide
- MedicosNotes.com

Interpretations

A positive Hoffmann’s reflex and finger jerks suggest hypertonia, but can occur in healthy individuals, and are not useful signs in isolation. In cerebellar diseases, the reflexes may be pendular, and muscle contraction and relaxation tend to be slow, but these are not sensitive or specific to cerebellar signs.

Comparisons to Babinski sign

Hoffmann's sign is often considered the

upper limb The upper limbs or upper extremities are the forelimbs of an upright-postured tetrapod vertebrate, extending from the scapulae and clavicles down to and including the digits, including all the musculatures and ligaments involved with the shoulde ...

equivalent of the Babinski sign test. Hoffmann's reflex is often erroneously confused with Babinski's. However the two reflexes are quite different, and should not be equated with each other. A positive

Babinski sign The plantar reflex is a reflex elicited when the sole of the foot is stimulated with a blunt instrument. The reflex can take one of two forms. In healthy adults, the plantar reflex causes a downward response of the hallux (flexion). An upward re ...

is considered a pathological sign of

upper motor neuron Upper motor neurons (UMNs) is a term introduced by William Gowers in 1886. They are found in the cerebral cortex and brainstem and carry information down to activate interneurons and lower motor neurons, which in turn directly signal muscles t ...

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 Hoffmann'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 is their mechanism of reflex. Hoffmann's reflex is a deep tendon reflex (spindle fibre) with a monosynaptic reflex pathway in

Rexed lamina The Rexed laminae comprise a system of ten layers of grey matter (I–X), identified in the early 1950s by Bror Rexed to label portions of the grey columns of the spinal cord. Similar to Brodmann areas, they are defined by their cellular structur ...

IX of the

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the spi ...

, normally fully inhibited by descending input. On the other hand, the plantar reflex is more complicated and not a deep tendon reflex, and its pathway is both more complicated and not fully understood. 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 Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND) or Lou Gehrig's disease, is a neurodegenerative disease that results in the progressive loss of motor neurons that control voluntary muscles. ALS is the most comm ...

References

External links

Cervical Spondylosis: Diagnosis and Management
- emedicine.com
Hoffmann sign
- Stedman's Dictionary

link of the exam performed with a positive Hoffman's sign {{Eponymous medical signs for nervous system Reflexes

Procedure

Interpretations

Comparisons to Babinski sign

See also

References

External links