Not an official “type” of Chiari, but a term used to describe a patient with a hindbrain herniation < 5mm, and no diagnoses due to the size of the herniation. With so many medical professionals still ignorant of the impact of obstructed cerebrospinal fluid, as made evident in the Chiari Zero studies, many patients with these smaller herniations are continuing to go undiagnosed and the blockage of cerebrospinal fluid continues to cause them problems.