The term hydrocephalus is derived from two words: “hydro” meaning water, and “cephalus” referring to the head. Hydrocephalus is a condition in which excess cerebrospinal fluid (CSF) builds up within the ventricles (fluid-containing cavities) of the brain and may increase pressure within the head. Although hydrocephalus is often described as “water on the brain,” the “water” is actually CSF, a clear fluid surrounding the brain and spinal cord. CSF has three crucial functions: 1) it acts as a “shock absorber” for the brain and spinal cord; 2) it acts as a vehicle for delivering nutrients to the brain and removing waste; and 3) it flows between the cranium and spine to regulate changes in pressure within the brain. Hydrocephalus can occur at any age, but is most common in infants and adults age 60 and older. According to the National Institute of Neurological Disorders and Stroke, hydrocephalus is believed to affect approximately one in every 500 children. The majority of these cases are often diagnosed before birth, at the time of delivery, or in early childhood. The term hydrocephalus is derived from two words: “hydro” meaning water, and “cephalus” referring to the head.