The Chaddock reflex is a diagnostic

reflex 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 ...

similar to the

Babinski reflex 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 ...

. Chaddock's sign is present when stroking of the

lateral malleolus A malleolus is the bony prominence on each side of the human ankle. Each leg is supported by two bones, the tibia on the inner side (medial) of the leg and the fibula on the outer side (lateral) of the leg. The medial malleolus is the promine ...

causes extension of the great toe, indicating damage to 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 was identified by

Charles Gilbert Chaddock Charles Gilbert Chaddock (November 14, 1861 – July 20, 1936) was an American neurologist, psychiatrist, and translator. He is remembered for describing the Chaddock reflex and is credited with the coinage of the terms ''bisexuality'', ''heteros ...

in 1911.

References

Diagnostic neurology Reflexes {{med-sign-stub