[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Clinical exam](https://durgical.com/en/clinical-exam/) › [Nervous system](https://durgical.com/en/clinical-exam/#a-neuro) › Hoffmann sign and clonus [Clinical exam](https://durgical.com/en/clinical-exam/) · [Nervous system](https://durgical.com/en/clinical-exam/#a-neuro) # Hoffmann sign and clonus - Sign Two signs of brisk reflexes: the thumb flexes when the middle fingernail is flicked, and the foot beats on its own when stretched. Updated 2026-11-01 **See it in 3D:** [Spinal cord](https://durgical.com/en/anatomy/spinal-cord/) · [Neck nerve roots](https://durgical.com/en/anatomy/anterior-root-of-spinal-nerve/) · [Achilles tendon](https://durgical.com/en/anatomy/calcaneal-tendon/) ## Key points - Hoffmann: flick the distal phalanx of the middle finger and the thumb and index finger flex. - Bilateral Hoffmann with brisk leg reflexes suggests cervical myelopathy. - Sustained clonus (lasts as long as the stretch is held) = upper motor neuron; it matches a 4+ reflex. - A few beats that fade can be seen in healthy people with brisk reflexes. - An isolated, symmetric Hoffmann can be found in healthy people. ## What it is The Hoffmann sign is involuntary flexion of the thumb and index finger when the nail of the middle finger is flicked; it is the hand's version of hyperreflexia. Clonus is a rhythmic series of contractions that appears when a muscle is stretched suddenly and held, mostly at the ankle. Both mean the reflex arc is released by an upper motor neuron lesion. ## The anatomy it tests - Hoffmann: the finger flexor reflex arc (C8 and T1 roots) released from corticospinal inhibition; a high cervical lesion brings it out. - Ankle clonus: the triceps surae stretch reflex (S1), which repeats unchecked when descending inhibition fails. - The lesion is in the corticospinal tract of the brain or spinal cord. ## How to elicit it - Hoffmann: the patient's hand relaxed, wrist slightly extended, middle finger held between the examiner's fingers. - The examiner places a thumb on the middle fingernail and flicks it downwards quickly. - Watch whether the thumb and index finger flex; repeat on the other hand. - Ankle clonus: patient lying down, knee bent and supported by the examiner's hand. - With the other hand, the examiner dorsiflexes the foot briskly and keeps the pressure on. - Count the rhythmic beats and note whether they fade or are sustained. ## What a positive result means - A positive Hoffmann and sustained clonus: an upper motor neuron lesion above the level of the reflex. - Causes: cervical spondylotic myelopathy, multiple sclerosis, stroke, spinal cord tumour or trauma, amyotrophic lateral sclerosis. - An asymmetric Hoffmann carries more weight than a symmetric one. - Its absence does not rule out myelopathy. ## Usefulness and limits - The Hoffmann sign has limited sensitivity for cervical myelopathy; MRI confirms the lesion. - A tense foot or slow dorsiflexion can stop clonus from appearing. ## Test yourself Think of the answer, then tap the question to see it. ## What is the Hoffmann sign? Involuntary flexion of the thumb and index finger when the middle fingernail is flicked downwards; it shows hyperreflexia from an upper motor neuron lesion. ## Which kind of clonus is abnormal? Sustained clonus, which lasts as long as the stretch is held; a few beats that fade can be normal. ## What does a bilateral Hoffmann with brisk leg reflexes suggest in an older adult with clumsy hands? Cervical myelopathy, for example spondylotic, which is confirmed with MRI. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/clinical-exam/hoffmann-sign-and-clonus/) ## See it in 3D The structures of Durgical's 3D anatomy where it is found. - [Spinal cord](https://durgical.com/en/anatomy/spinal-cord/) - [Neck nerve roots](https://durgical.com/en/anatomy/anterior-root-of-spinal-nerve/) - [Achilles tendon](https://durgical.com/en/anatomy/calcaneal-tendon/) ## Related - [Deep tendon reflexes and their grading](https://durgical.com/en/clinical-exam/deep-tendon-reflexes-and-their-grading/) - [Babinski sign](https://durgical.com/en/clinical-exam/babinski-sign/) - [Upper vs lower motor neuron syndrome](https://durgical.com/en/clinical-exam/upper-vs-lower-motor-neuron-syndrome/) - [Spinal cord syndromes: complete, Brown-Séquard, central, anterior](https://durgical.com/en/clinical-exam/spinal-cord-syndromes-complete-brown-sequard-central-anterior/) ## Related conditions - [Degenerative cervical myelopathy](https://durgical.com/en/conditions/degenerative-cervical-myelopathy/) - [Multiple sclerosis](https://durgical.com/en/conditions/multiple-sclerosis/) - [Spinal cord injury](https://durgical.com/en/conditions/spinal-cord-injury/) - [Ischaemic stroke](https://durgical.com/en/conditions/ischaemic-stroke/) [← All of the clinical exam](https://durgical.com/en/clinical-exam/) Educational content on the clinical exam; it is learned and practised under supervision. It does not replace assessment by a health professional and is not for self-diagnosis. Sources: [How To Assess Reflexes](https://www.msdmanuals.com/professional/neurologic-disorders/neurologic-examination/how-to-assess-reflexes) (MSD Manual Professional Edition, 2024); [26.2 Physical Assessment - Clinical Nursing Skills](https://openstax.org/books/clinical-nursing-skills/pages/26-2-physical-assessment) (OpenStax, 2024); [Overview of Spinal Cord Disorders](https://www.msdmanuals.com/professional/neurologic-disorders/spinal-cord-disorders/overview-of-spinal-cord-disorders) (MSD Manual Professional Edition, 2024). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/clinical-exam/hoffmann-sign-and-clonus/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/clinical-exam/hoffmann-sign-and-clonus/