Arnold (1894) and Chiari (1896) described the displacement of the cerebellar tonsils through the foramen magnum into the initial part of the spinal canal. However, they related this observation exclusively to the simultaneous occurrence of malformations. Alquier (1905) and Henschen (1910) reported such tonsillar alterations in intracranial tumours. Cushing (1917 and 1929) recognized the connection with the increase of intracranial pressure and coined the term “cerebellar pressure cone”.
