A device for penetrating tissue includes an elongated element having a distal end, a proximal end, a body extending between the distal and the proximal ends, and a lumen located within at least a portion of the body, wherein the lumen has a cross-sectional shape that is a polygon. A device for penetrating tissue includes an elongated element having a distal end, a proximal end, and a body extending between the distal and the proximal ends, at least a portion of the body having a cross-sectional profile that is a polygon, wherein the elongated element is a cannula.
