Patent ID: 8328836

Claim:
A tissue-penetrating device, comprising: a flexible hollow elongate shaft having a tissue-penetrating tip at a distal end thereof; an outer sheath disposed around at least a portion of the hollow elongate shaft; a plunger disposed within the tissue-penetrating tip and movable relative to the tissue-penetrating tip between a distal position in which the plunger is distal of the tissue-penetrating tip to prevent tissue penetration, and a proximal position in which the plunger is proximal of the tissue-penetrating tip to allow the tip to penetrate tissue, wherein the plunger is adapted to move from the distal position to the proximal position when the plunger is advanced into a tissue surface; a biasing element configured to bias the plunger to the distal position; a stylet extending through the hollow elongate shaft, the biasing element being coupled between a distal end of the stylet and a proximal end of the plunger; and a depth gauge associated with the hollow elongate shaft and effective to position the tissue-penetrating tip of the elongate shaft relative to the outer sheath.