What does a positive Babinski reflex indicate?

A positive Babinski reflex is characterized by the extension of the big toe with splaying of the other toes when the sole of the foot is stroked. In adults, this response is indicative of central nervous system (CNS) function rather than normal neurological function, as an intact adult reflex should cause the toes to curl downwards.

The presence of a positive Babinski reflex in an adult suggests dysfunction in the corticospinal tract, which may result from various neurologic conditions, including possible spinal cord damage. The corticospinal tract is essential for voluntary motor control, and injuries affecting this pathway can lead to abnormal reflexes, such as the Babinski sign.

In contrast, a negative Babinski reflex—characterized by the normal downward curling of the toes—indicates that the neurological pathways are intact in an adult, which aligns more closely with normal neurological function. Therefore, a positive Babinski reflex is a significant clinical indicator of potential underlying neurological problems, including spinal cord damage.