and is less likely therefor to fail such as by kinking when it is being inserted into position within a patient referring now to fig8 when a catheter 40 is moved through the lumen 12 of the needle 20 the distal end 41 thereof first contacts the detent 21 which causes an initial deflection of the catheter distal end 41 toward the side opening 14 further movement of the catheter 40 down the lumen 12 causes the distal end 41 to move past the tab 18 and out of the side opening 14 as shown in fig9 a third embodiment of the invention is shown with the catheter 40 in this embodiment the catheter 40 is initially deflected by the detent 21 a sufficient lateral distance to allow the distal end 41 to pass out of the side opening 14 as the catheter 40 continues to move down the lumen 12 as is evident the height of the detent 21 in this embodiment of the invention may need to be adjusted depending on the particular flexibility characteristics of the catheter 40 in order to ensure that the distal end 41 thereof is sufficiently deflected to pass through the side opening 14 in this respect the height of the detent 21 is limited only by the need to allow the lumen 12 to remain of a sufficient diameter at the point of the detent 21 for passage of the catheter 40 in other words the restricted diameter of the lumen 12 caused by the detent 21 must be at least slightly greater than the.