A medical fluid connector is described that includes a first fluid connector portion that can be connected to a second fluid connector portion. The first fluid connector portion includes a first locking member, a lumen and a septum for sealing the lumen. The second fluid connector portion includes a second locking member, a lumen and a hollow needle that is retained in and protrudes from the aperture at the end of the lumen. The variation in cross-sectional area of the fluid path through the fluid connector portion is less than 1 mm2 to reduce mixing effects. The use of such a connector for neurosurgical purposes is described.