Abstract: A ventricular catheter includes an external ventricular drainage (EVD) catheter and has at least one conduit formed in the wall of the EVD catheter. The conduit opens at a side port of the wall at an angle to the EVD catheter. The side port is formed in the wall to allow a probe to be extended from the conduit at the angle into brain tissue that is not altered by the insertion of the EVD catheter. The ventricular catheter has an oval shape to minimize the total cross-sectional area while still allowing the necessary number of conduits.