[Antonio Pacchioni (1665-1726): pioneer studies on the dura mater].
Clustering of arachnoid villi along the sagittal sinus gives rise to the so-called "Pacchionian Granulations". These structures were originally described in 1705 by Antonio Pacchioni, an Italian scientist. Born in Reggio Emilia in 1665, he graduated in Medicine in his hometown and later moved to Rome were he built up a successful career by dedicating to medical practice as well as to research and teaching. He became friend and often collaborated with some of the leading scientists of his age: Lancisi, Malpighi and Morgagni among the others. Moreover he carefully followed research developments in Europe as testified by frequent quoting of foreign authors in his works. He devoted himself to the elucidation of structure and function of Dura Mater, often by using new techniques of maceration of anatomic specimens in various fluids. Among Pacchioni's works, the "Dissertatio epistolaris de glandulis conglobatis Durae Meningis humanae" (1705) is particularly well known and contains the first description of arachnoidal granulations. He compared Dura to cardiac muscle and attributed to its "glandulae" (glands) the faculty of secreting lymph for lubrification of the sliding movements between meninges and brain during contractions. He died in Rome in 1726. Three centuries after Pacchioni's death fine structure of arachnoid villi hasn't been fully elucidated; moreover many questions on mechanisms underlying CSF absorption remain unanswered.