c 34 clamp 200 probe clip 110 is required to flex in order for protuberances 210 and 230 to be able to pushed into the appropriate detents however if probe clip 110 is too flexible it will not hold onto the probe tightly and if probe clip 110 is too rigid it may damage the probe when it is pushed onto it or removed from it as those skilled in the art will readily appreciate it is possible to fabricate a needle guide without using a probe clip lock in such an embodiment the probe clip will be retained on the probe because of the rigidity of the probe clip however in the preferred embodiment of the present invention probe clip 110 is preferably formed of a somewhat rigid material for example injection molded plastic and as a result 34 c 34 clamp 200 is somewhat rigid channels 240 and 250 enable one to flex 34 c 34 clamp 200 to a greater extent than would be possible in their absence this flexing enables probe clip 110 to be more easily detachably affixed to ultrasound probe 300 when probe clip 110 is affixed to ultrasound probe 300 probe clip lock 120 is engaged so that channels 240 and 250 are filled by legs 571 and 572 respectively of probe clip lock 120 see fig3 when channels 240 and 250 are thusly filled the flexibility of 34 c 34 clamp 200 is greatly reduced and this serves to lock probe clip 110 so it is securely affixed to ultrasound probe 300 fig3 shows in pictorial form a perspective view of probe clip lock 120 which is.