A TROCAR

摘要

A generally cylindrical trocar, for forming a hole in the abdominal wall of a patient to receive a cannula, comprises: cutting means (6); support means (10, 14) for the cutting means, a guard (24) mounted on the support means for axial movement between a forward position in which the guard covers the cutting means and a retracted position in which the cutting means are exposed, and a spring (42) acting between the support means and the guard to bias the guard towards its forward position. The cutting means is provided by two generally triangular blades (2, 4) forming a cruciform blade arrangement with cutting edges (3) inclined to the axis of the trocar.