[Endoscopic ventricular anatomy].

Neurosurgical endoscopy enables in situ exploration of the dilated ventricular system, primarily for therapeutic rather than diagnostic purposes. Ventriculocisternostomy in patients with obstructive hydrocephalus is the most widely performed endoscopic procedure. Perfect knowledge of the intraventricular anatomy is necessary for proper endoscopic navigation so the operator always recognizes the position of the endoscope and the anatomic structures encountered. Endoscopic anatomy in this situation is different from normal anatomy because of the hydrocephalus. Anatomic landmarks must be reassessed. We present here this "new" anatomy.