A method of relieving vacuum in a biopsy apparatus includes applying vacuum through at least one motor to an inner cannula lumen； providing a continuously open leak path that permits fluid communication between the outer cannula lumen and atmosphere, wherein fluid is drawn from the leak path through the outer cannula； retracting the inner cannula proximally to permit tissue to prolapse into a tissue receiving opening of the outer cannula due to the vacuum； translating the inner cannula distally to sever the prolapsed tissue； aspirating the severed tissue through the inner cannula lumen； and selectively relieving vacuum distally of the severed tissue by retracting the inner cannula proximally to permit the inner cannula lumen to communicate with the respective outer cannula lumen and the leak path while a portion of the biopsy apparatus, including the tissue receiving opening, is positioned within tissue.
