Patent ID: 6989003

Claim:
A trocar comprising: an elongated cannula member having a first camming surface formed on a proximal end thereof and a radially-expandable opening formed on a distal end thereof; an elongated obturator adapted to be inserted into the cannula for rotational and axial movement therein, said obturator comprising a shaft having a distal end; a point formed on the distal end of the shaft, said point tapering distally from a maximum diameter band and tapering proximally from said band to the shaft, said band being larger in girth than the distal cannula opening; said band being distally adjacent the distal cannula opening when the obturator is substantially fully inserted into the cannula; and a cap formed on a proximal end of the obturator, said cap having a second camming surface positioned thereon for engagement with the first camming surface when the obturator is substantially fully inserted into the cannula, said first and second camming surfaces being effective to cause proximal axial displacement of the obturator with respect to the cannula member when the cap is rotated with respect to the cannula member, said distal cannula opening expanding radially as the maximum diameter band moves proximally through it; and wherein said radially-expandable opening at the first end of the cannula member comprises a smooth and continuous circumferential wall.