Patent ID: 8133245

Claim:
A surgical apparatus for penetrating tissue, which comprises: an outer member defining a longitudinal axis and having proximal and distal ends, the outer member having an outer peripheral wall and a longitudinal guide channel including a distal end surface; an inner member at least partially disposed within the longitudinal guide channel of the outer member, the inner member including a penetrating member positioned proximally adjacent to and spaced-apart from the distal end of the inner member, the penetrating member having a substantially annular peripheral edge adapted to penetrate tissue, the inner member configured to traverse the guide channel upon longitudinal movement of the outer member relative to the inner member between first and second longitudinal positions, wherein, in the first position, the distal end of the inner member is spaced-apart from the distal end surface of the guide channel of the outer member such that the annular peripheral edge of the penetrating member is substantially confined within the outer peripheral wall of the outer member, and, wherein, in the second position, the distal end of the inner member traverses the guide channel to contact the distal end surface of the guide channel such that the annular peripheral edge of the penetrating member is at least partially exposed from the outer peripheral wall of the outer member to facilitate penetration through tissue.