John Cleland was born in 1835. He studied medicine in Edinburgh, becoming a doctor in 1856. He was appointed as Professor of Anatomy in Glasgow in 1877. He published extensively and in 1883 was the first to describe what we now know as the Chiari malformation. Cleland died in 1925.

Hans Chiari was born in Vienna in 1851. In 1883 he became Professor of Pathological Anatomy in Prague. In 1906 he moved and took up a similar post in Strasburg. He, too, wrote and published extensively. Whilst in Prague he produced, in 1891, his first description of the malformation that now bears his name. He published a more detailed account of the abnormality in 1895 and again in 1896. Chiari acknowledged Cleland’s contribution to our understanding of hindbrain abnormalities in his publication of 1895. Chiari died in 1916.

Julius Arnold was born in Zurich in 1835. He qualified as a doctor of medicine in 1859. In 1866 he became Professor of Pathological Anatomy in Heidelberg. Like Cleland and Chiari, he produced a large number of publications in his lifetime. In 1894, 3 years after Chiari’s original article appeared, Arnold also described an abnormality at the craniovertebral junction, affecting the brain stem, fourth ventricle and cerebellum. Two of Arnold’s students later emphasised the associated bony abnormalities at the base of the skull, and it was they who coined the term Arnold-Chiari malformation. Arnold died in 1915.

Augustine Morvan was born in 1819. He studied medicine in Brest and then Paris. He qualified as a doctor in 1843. Morvan was another prolific writer and he described the syndrome that bears his name in 1883. He gave, at the same time, a thorough description of syringomyelia. Morvan died in 1897.

Guy Hinsdale was born in 1858. He was a neurologist at the Infirmary for Nervous Disease in Philadelphia. He is most recognised for his role in developing instruments to measure and record postural sway (Lanska 2001). Hinsdale wrote an illustrated essay on syringomyelia which was awarded the Alvarenga Prize of the College of Physicians in 1895, i.e. 4 years after Hans Chiari’s first description of hindbrain herniation (Hinsdale 1897). The essay includes a bibliography of 514 references relating to syringomyelia and reviews a staggering 120 cases. There is detailed description of the histopathology and clinical signs in particular scoliosis and the distribution of sensory deficits. In the aetiology section he describes, amongst other causes, seven people (in 2 families) with hereditary syringomyelia. Under a section entitled Syringomyelia associated with other diseases, he lists spina bifida and chronic hydrocephalus referencing Chiari. Guy Hinsdale died in 1948.

Cornelis Joachimus van Houweninge Graftdijk was born 1888 in Giessendam, Netherlands. He was a surgeon at the Diaconessenhuis hospital in Leiden. Van Houweninge Graftdijk is credited with the first description of a hindbrain decompression which he performed in 1930 on a patient with myelomeningocele- and ventriculogram-proven hindbrain herniation (Mortazavi et al. 2011b). Unfortunately the patient died. Most importantly he realised the clinical signs and hydrocephalous was due to obstruction of cerebrospinal fluid flow through the foramen magnum by the hindbrain. The description of the surgery was in his thesis for a Doctorate of Medicine entitled Over Hydrocephalus (about hydrocephalus) (Van Houweninge Graftdijk 1932). Perhaps his interest in this subject was kindled because his older brother had died of this disease. Van Houweninge Graftdijk died in 1956.

W. James Gardner was born in 1898, in McKeesport, Pennsylvania, USA. He founded the Department of Neurological Surgery at the Cleveland Clinic Foundation, in Ohio. Testimonials to him note his inventiveness, citing his design of a neurosurgical operating chair and the use of gravity suits to facilitate operating in the sitting position. He also designed an air mattress for the prevention of bed sores and a pneumatic splint for treating fractures (Hartwell 1885; Pillay et al. 1992; Nathoo et al. 2004). His name is widely associated with the skull traction apparatus that he designed and Gardner-Wells tongs are still used today, as a simple means of applying effective cervical traction, under local anaesthetic and without the need to drill into the skull. Today Gardner’s name is perhaps most widely quoted in the neurosurgical literature in association with Chiari and syringomyelia. He proposed a theory of syringomyelia which was widely accepted for more than two decades (Pillay et al. 1992). This assumed the presence of impaired ventricular drainage and a communication between the fourth ventricle and the central canal of the spinal cord. Most significantly, Gardner suggested that arterial pulse pressure waves, acting upon the CSF, created a “water-hammer” effect, driving CSF through the obex and into the central canal. The role of arterial energies in filling syrinx cavities, albeit not via the obex, is still supported by current theories – see Chap. 8. Importantly, Gardner turned surgical attention away from the syrinx itself and toward the craniovertebral junction. He championed the decompression that is still performed today, in one form or another, albeit without the obex plugging that he recommended. Gardner died in Ogden, Utah in 1987.