Chaddock reflex [Charles G. Chaddock, American neurologist, 1861–1936] , an abnormal reflex, induced by firmly stroking the ulnar surface of the forearm, characterized by flexion of the wrist and extension of the fingers in fanlike position. It is seen on the affected side in hemiplegia. Compare Gordon’s reflex, Oppenheim reflex. See also Babinski’s reflex.