This is the most commonly carried hammer which most people have seen used when they go to the doctor. It is also incorrectly called “the triangle hammer”, “the rubber hammer”, and I’ve even heard it referred to as “the tomahawk”.
John Madison Taylor (1855-1931) graduated medical school from University of Pennsylvania in 1878, and then practiced pediatrics, neurology, and physical medicine in Philadelphia.
Taylor displayed his hammer at the February 27, 1888 meeting of the Philadelphia Neurological Society. It was well described in the minutes of the meeting:
[Taylor’s hammer] was devised to serve as nearly as possible all ends for which a hammer is likely to be called into use by clinicians… In shape it is a cone flattened on the opposite side, with apex and base carefully beveled or rounded, of about the thickness throughout of the human index finger. The material is moderately soft rubber. It is held by an encircling band of metal midway between the apex and base transversely, and from it, on the edge, depends the straight handle. The handle is rigid though light, it being Dr. Taylor’s opinion that this had better be under the full control of the wilder. If elastic as recommended by some, an element of uncertainty enters in the degree of force used in the blow. The special feature of this hammer is that the shape of the striking surface is like the outer surface of the extended hand, palm downward, which is most often used in obtaining tendon jerk. The rounded apex is adopted to reach the biceps tendon at the bend of the arm [and according to S. Weir Mitchell, “to get muscle response by direct blow on the muscle.”] …. This little tool will also well serve to elicit chest sounds, to percuss the abdomen, and in fact, is useful whenever an elastic hammer is needed. The material being of soft rubber, the blow does not hurt the intercepting fingers as does the hammer usually employed to strike the tendons and muscles.
The original version had an open loop handle, but around 1920 they were designed with a solid handle with a pointed tip for eliciting cutaneous reflexes.
Primary reference: Lanska, DJ; Neurology Nov 1989 p1542-9; The History of Reflex Hammers History of the reflex hammer