The space between the arachnoid and pia meningeal layers encasing the brain is a landscape of connective tissue, blood vessels, and cerebrospinal fluid. Scientists debate how that fluid moves within ...

Chiari malformation, an anomaly of the posterior cranial fossa, also known as Arnold–Chiari malformation, was described in autopsies by Hans Chiari, an Austrian pathologist, in 1891. He defined four ...