Patent ID: 7666172

Claim:
A needle, comprising a tubular side wall defining an internal bore, the tubular side wall further defining a longitudinal axis; a concave end wall disposed at a distal end of the side wall, the end wall angled relative to the longitudinal axis; a closed tip defined by a region that includes a distal-most interface of the end wall and the tubular side wall; and a proximal point defined by a region that includes a proximal-most interface of the end wall and the tubular side wall; wherein a distal opening is defined spaced from the closed tip and provides access to the internal bore; wherein the end wall has a variable concavity profile, as viewed in sequential cross sections taken normal to the longitudinal axis; and wherein the concavity of the end wall decreases as the end wall extends away from the closed tip, as viewed in sequential cross sections taken normal to the longitudinal axis, so that the end wall is comparatively more concave in proximity to the closed tip than it is in proximity to the proximal point.