Testing the Babinski reflex involves stroking the sole of the foot with a firm, pointed object and watching what the big toe does. In a healthy adult, the toes curl downward. In someone with damage to the nerve pathway that runs from the brain down through the spinal cord, the big toe extends upward instead, sometimes with the other toes fanning apart. That upward movement is called a positive Babinski sign, and it has been one of the most widely used bedside neurological tests since the late 1890s. But the test is trickier to perform and interpret than it looks, and its reliability depends heavily on technique, the patient’s age, and even what happened to the patient in the hours before the exam.
How to Perform the Test
You need a blunt but somewhat pointed instrument. The traditional choice is a neurological reflex hammer’s pointed end, a broken tongue depressor, or a disposable key. The patient should be lying down with their leg extended and relaxed. Grip the ankle gently to stabilize the foot, and with your instrument, apply firm pressure along the lateral (outer) edge of the sole, starting near the heel and moving toward the ball of the foot. Research on the optimal stroking pattern found that a straight line up the lateral sole to about the midfoot is the most reliable way to get an accurate response.1PubMed. A systematic and quantitative evaluation of plantar stimulation: The effect of type, pattern, force of stimulation in eliciting an accurate plantar response Many textbooks describe curving the stroke medially across the ball of the foot, but the evidence suggests the straight-line approach along the lateral border works better.
Pressure matters. Too light, and you may not trigger any meaningful response. Too hard, and you cause pain, which can provoke a withdrawal reflex that mimics an upgoing toe but is actually just the patient yanking their foot away. Studies measuring the forces clinicians use during the test found that the force applied correlated with pain scores, and that harder strokes did influence how much the big toe moved.2PubMed. Kinematic and kinetic analysis of the inter- and intra-applicator assessment of the Babinski reflex The goal is a brisk, moderately firm stroke that the patient can feel clearly but does not find sharp or distressing. If the patient flinches and pulls away, you likely pressed too hard, and whatever the toe did is unreliable.
What You Are Looking For
The normal adult response, called a flexor plantar response, is the toes curling downward (plantarflexion). The abnormal response, the extensor plantar response or positive Babinski sign, is the big toe dorsiflexing, meaning it bends upward toward the shin. Often, but not always, the smaller toes fan outward at the same time. Joseph Babinski first described this phenomenon in 1896, initially noting the extension of all the toes, and two years later he refined the description to focus specifically on the upward movement of the big toe.3PubMed. 100 years of the Babinski sign
A genuinely positive Babinski sign is not a brief twitch. Research comparing pathological responses to those occasionally seen in healthy people found that in patients with real upper motor neuron damage, the big toe extension was sustained throughout the entire duration of the stimulus in over 90% of cases, compared to about three-quarters of the time in healthy controls who happened to show some toe movement.4PubMed Central. Differentiating Extensor Plantar Response in Pathological and Normal Population The pathological response was also triggered more easily: roughly 89% appeared when the stimulus had only reached the mid-lateral sole, while in controls, fewer than 12% responded that early. So if the big toe shoots up right away and stays up the whole time you are stroking, that carries more diagnostic weight than a brief upward flicker that quickly resolves.
Why a Positive Sign Matters
Babinski recognized that the upgoing toe was linked to dysfunction of the pyramidal system, the bundle of nerve fibers (often called the corticospinal tract) running from the brain’s motor cortex down through the brainstem and spinal cord.5PubMed. The Babinski sign: the first hundred years When that tract is working normally, it suppresses the primitive extensor reflex. When it is damaged, the suppression lifts and the old reflex re-emerges. The causes of such damage span a wide range: stroke, brain tumors, multiple sclerosis, spinal cord compression, amyotrophic lateral sclerosis, and traumatic brain injury are among the most common.
An important detail is whether the sign appears on one side or both. A unilateral positive Babinski, present on only one foot, often points to a focal lesion such as a stroke or tumor affecting one hemisphere of the brain or one side of the spinal cord. A bilateral sign, present on both feet, is more suggestive of widespread or midline damage, as seen in conditions like spinal cord compression at a certain level, advanced multiple sclerosis, or diffuse brain injury.
The Babinski Reflex in Infants and Young Children
A positive Babinski sign does not mean the same thing in a baby as it does in an adult. Newborns and infants routinely show the extensor plantar response, and this is completely normal. The corticospinal tract is not fully myelinated at birth, meaning the nerve fibers have not yet been coated with the insulation that allows rapid signal transmission. Without that mature wiring, the brain cannot suppress the primitive toe-extension reflex. Early research tracked this pattern in individual infants over time and confirmed that the Babinski sign may be present from birth and then gradually disappear as myelination matures, generally by the age of two or three.6JAMA Pediatrics. A Longitudinal Study of the Babinski and Plantar Grasp Reflexes in Infancy
The timeline is not precise. Some healthy toddlers lose the reflex by 12 months; others retain it past their second birthday. A Babinski sign in a six-month-old is not alarming. A persistent upgoing toe in a child well past the age of three or four, however, warrants investigation because it could suggest that the corticospinal tract has not developed normally or has been damaged.
How Reliable Is the Test, Really?
The Babinski sign occupies a strange place in clinical neurology: it is probably the single most famous bedside neurological test, yet its reliability is surprisingly modest. Across several studies, the sensitivity of the test hovers around 50%, meaning that roughly half the patients who genuinely have corticospinal tract damage will show a positive Babinski sign. Its specificity, though, is much stronger. One study found specificity of about 86%,7PubMed. Accuracy and reliability of Babinski sign versus finger and foot tapping in the diagnosis of corticospinal tract lesions while another reported it as high as 99%.8PubMed. Accuracy of the Babinski sign in the identification of pyramidal tract dysfunction
In plain terms: when the test is positive, there is a very high chance something is actually wrong. But when it is negative, you cannot breathe easy, because the test misses about half of real cases. A negative Babinski sign does not rule out corticospinal tract damage.
Agreement between examiners is another weak spot. When different clinicians test the same patient, they often disagree on whether the toe went up or down. One study found only fair agreement for the Babinski sign, with a kappa of 0.30, compared with substantial agreement (kappa 0.73) when clinicians instead tested for subtle weakness by watching the patient tap their foot.9PubMed. Should the Babinski sign be part of the routine neurologic examination? Another study comparing medical students with a neurologist found similarly low interobserver agreement for the Babinski sign (kappa 0.45), while agreement for finger and foot tapping was much higher (kappa 0.83).7PubMed. Accuracy and reliability of Babinski sign versus finger and foot tapping in the diagnosis of corticospinal tract lesions
This does not mean the test is useless, but it does mean experienced neurologists treat it as one data point among many rather than a standalone verdict. A positive Babinski sign alongside other upper motor neuron findings such as increased muscle tone, brisk reflexes, and weakness is a powerful combination. An isolated positive sign in an otherwise normal exam calls for caution and likely repeat testing.
Alternative Ways to Test the Same Reflex
The classic sole-of-the-foot stroke is not the only way to check for an extensor plantar response. Several named variants exist, the most useful being the Chaddock sign. Instead of stroking the sole, you stroke the lateral surface of the foot itself, along the outside edge below the ankle. Charles Chaddock described this modification after studying Babinski’s work, and the idea is that stimulation of the outer foot surface triggers the same toe extension when there is pyramidal tract damage.10PubMed. History of the extensor plantar response: Babinski and Chaddock signs
The Oppenheim test is another alternative: you run your thumb and finger down the front of the shin bone from knee toward ankle with firm pressure. All three tests aim to provoke the same underlying reflex, but they are not interchangeable. A study comparing all three found that the Babinski and Chaddock methods had roughly similar sensitivity (about 60% and 55%, respectively) and positive predictive value (about 70% and 67%), while the Oppenheim test lagged behind with a sensitivity of only 30%.11PubMed Central. The plantar reflex: A study of observer agreement, sensitivity, and observer bias The Babinski and Chaddock methods also showed the strongest agreement with each other, though even that agreement was described as weak.
The practical takeaway is that the Chaddock sign is the best backup when the standard Babinski test is ambiguous or when the sole of the foot cannot be tested, for example because of a wound, calluses, or extreme ticklishness that causes involuntary withdrawal. The Oppenheim test adds little on its own. Clinicians who want more confidence typically combine two or all three methods and look for consistency across them.
Telling a True Positive From a False Alarm
Several things can make the big toe go up even though there is nothing wrong with the corticospinal tract. The biggest confounder is the withdrawal response. If you press too hard or the patient is extremely ticklish, they may reflexively pull the entire foot away, and in doing so the toes extend. The key difference: in a true Babinski sign, the big toe extends while the rest of the foot stays relatively still, and the movement is slow and tonic (a sustained upward drift). In a withdrawal, the whole foot and leg jerk away together, and the toe movement is fast and ballistic.
Research on distinguishing pathological from incidental extensor responses found that reproducibility is a strong differentiator. In patients with confirmed corticospinal tract damage, nearly 90% had at least two consecutive positive Babinski responses when tested repeatedly, whereas only about 14% of healthy controls who showed an initial extensor response could reproduce it.4PubMed Central. Differentiating Extensor Plantar Response in Pathological and Normal Population So if you get an ambiguous result, test again. A genuinely pathological response will show up repeatedly, trigger earlier in the stroke, and stay sustained throughout.
Transient Babinski Signs in Otherwise Healthy People
Not every positive Babinski sign points to a permanent lesion. Certain temporary conditions can produce the reflex, and it resolves once the underlying cause clears. One well-documented scenario is general anesthesia. Studies of neurologically normal patients found that during the first hour of waking up from anesthesia, transient upgoing toes and other signs that would normally be called pathological appeared regularly.12PubMed. Neurologic changes during awakening from anesthesia One study comparing two anesthetic agents found that positive Babinski reflexes were more common after enflurane-based anesthesia than after isoflurane, with all neurological abnormalities resolving within 60 minutes.13PubMed. Neurological phenomena during emergence from enflurane or isoflurane anaesthesia
Beyond anesthesia, various toxic and metabolic disturbances can produce a temporary extensor plantar response. Severe hypoglycemia, hepatic encephalopathy, drug overdose, seizures (particularly in the postictal period right after a seizure ends), and deep sedation have all been reported as triggers.14The Journal of Emergency Medicine. Medical classic Joseph babinski: The phenomenon of the toes In these situations, the reflex often reverts to normal once the metabolic problem is corrected or the drug wears off. Clinicians need to interpret the Babinski sign in context: finding one during a post-seizure exam means something very different from finding one during a routine checkup.
Spinal Cord Injury and the Absent Babinski
You might assume that if someone has a complete spinal cord injury, the Babinski sign would always be positive, since the corticospinal tract is obviously disrupted. But it turns out the reality is more complicated. A study of patients with complete spinal cord injuries found the Babinski sign in only about half (49%) of them.15PubMed. The occurrence of the Babinski sign in complete spinal cord injury The presence or absence did not depend on the level of the injury. Instead, it correlated with muscle tone: patients who had developed significant spasticity tended to have a positive sign, while those without spasticity often did not. In many of the patients who lacked the sign, the reason turned out to be concurrent peripheral nerve damage, which disrupts the reflex arc at the lower level and prevents the toe from extending regardless of what is happening upstream.
This is a clinically important reminder that the Babinski reflex requires an intact peripheral pathway to work. If the nerves traveling from the spinal cord to the foot muscles are also damaged, you will not see an extensor response even when the corticospinal tract is completely severed. The same logic applies in patients with severe peripheral neuropathy from diabetes or other causes: a negative Babinski sign does not exclude central nervous system damage when the peripheral nerves are compromised.
Practical Tips for Getting a Clean Result
Given the test’s known weaknesses in reliability and the risk of confounders, a few practical habits make a difference:
- Warn the patient: Unexpected sole stimulation can cause a startle reflex that looks like withdrawal. Telling the patient what you are about to do reduces involuntary reactions.
- Test the resting foot: If the patient is tensing their foot or actively resisting, the result is unreliable. Make sure the leg is resting and the foot is relaxed.
- Stroke once, observe, then repeat: A single ambiguous result means little. Reproducible upward extension over two or three trials is far more convincing than a one-off flicker.
- Use moderate force: Hard enough to stimulate, not so hard it hurts. If the patient winces, you are pressing too hard, and any toe movement could be withdrawal rather than a true reflex.
- Watch the big toe specifically: Do not get distracted by the smaller toes or the general foot movement. The hallmark of the sign is isolated, sustained dorsiflexion of the great toe.
- Confirm with Chaddock if unclear: If the sole is too sensitive, calloused, or injured, try stroking the lateral foot instead. A consistent extensor response across both methods strengthens confidence in a positive finding.
When the Babinski Sign Shows Up During Anesthesia Recovery
Anesthesiologists and post-anesthesia care unit nurses encounter a specific practical dilemma. A patient wakes up from surgery and a routine neuro check finds upgoing toes. Does this mean the surgery damaged the brain or spinal cord, or is it just the anesthesia wearing off? The existing research suggests that in neurologically healthy patients undergoing minor procedures, transient Babinski signs during the first five to twenty minutes after anesthesia are common and resolve within an hour.13PubMed. Neurological phenomena during emergence from enflurane or isoflurane anaesthesia These signs typically appear alongside other transient abnormalities like exaggerated knee-jerk reflexes and shivering.12PubMed. Neurologic changes during awakening from anesthesia
The important clinical distinction is persistence. A Babinski sign that is still present an hour or more after the patient has fully regained consciousness and all other neurological signs have normalized is far more concerning than one found in a groggy patient ten minutes after the anesthetic is shut off. In high-risk surgeries, particularly spinal or intracranial procedures, serial neurological exams over the first hours of recovery give a much clearer picture than any single check.
Why the Test Survives Despite Its Limitations
Given its middling sensitivity and the well-documented disagreements between examiners, you might wonder why clinicians still bother with the Babinski sign at all. The answer lies in its extraordinary specificity. When the test is clearly positive, the odds that the person actually has corticospinal tract dysfunction are very high. One study calculated a positive likelihood ratio above 50, meaning a clear upgoing toe shifts the probability of real pyramidal tract disease dramatically upward.8PubMed. Accuracy of the Babinski sign in the identification of pyramidal tract dysfunction It also requires no equipment beyond something to stroke the foot with, takes seconds to perform, and can be done on unconscious or uncooperative patients who cannot follow commands for other neurological tests.
The test is most valuable in emergency settings, where speed matters and a patient may not be able to cooperate with a full examination. An unconscious person brought into an emergency room after a head injury cannot follow instructions to move their arms and legs on command, but you can still check for a Babinski sign. A clear positive result on one side in that scenario immediately raises suspicion for a focal brain lesion and can influence how urgently imaging is pursued. In that context, the test’s weaknesses in sensitivity are beside the point: you are not using it to screen; you are using it to catch a high-confidence signal when one exists.