Wiktionary
reflex hammer
n. (context medicine English) A tool used by physician to hit the body and test for certain reflexes.
Wikipedia
Reflex hammer
A reflex hammer is a medical instrument used by practitioners to test deep tendon reflexes. Testing for reflexes is an important part of the neurological physical examination in order to detect abnormalities in the central or peripheral nervous system.
Reflex hammers can also be used for chest percussion.
Usage examples of "reflex hammer".
Bellows took his reflex hammer and absently tried for deep tendon reflexes on Nancy Greenly's legs.