Lhermitte's sign. From observation to eponym.

The Lhermitte's sign was first described by Pierre Marie and Chatelin in 1917. Lhermitte reported on this symptom in 1920, and in 1924 he published the seminal article on the subject. In 1928, it was introduced to the American literature, and it was around that time that the symptom became well known. The historic development of this observation into an eponym is documented.