The present application relates to an access device for placing a medical article within a body space, comprising: a needle including a needle body having a longitudinal axis with a distal tip and a needle hub from which the needle body extends； a dilator including a dilator shaft and a dilator hub, the dilator shaft being disposed on and slideable along the needle body with the dilator hub being disposed distal of the needle hub； a medical article comprising a tubular section and a hub, the tubular section being disposed on and slideable along the dilator with the hub being disposed distal of the dilator hub； a track extending from the dilator hub in a proximal direction； and a locking mechanism operably disposed between the track and the needle so as to selectively inhibit proximal movement of the needle relative to the dilator.
