His name is lent to a disorder known as Arnold-Chiari malformation, which occurs when the cerebellar tonsils and the medulla oblongata protrude through the foramen magnum into the spinal canal. Arnold described this malformation in an infant who died shortly after delivery, and published his account in an 1894 paper titled Myelocyste, Transposition von Gewebskeimen und Sympodie. In 1891, Austrian pathologist Hans Chiari (1851-1916) also described this disorder, three years prior to Arnold's findings. In 1907, two of Dr. Arnold's students coined the eponym of "Arnold-Chiari malformation" in honor of both men.