| 摘要 |
A retractable penetrating instrument for providing fluid communication with a body cavity, which comprises a cannula (14) having a distal end (78) for positioning in the body cavity and a proximal end (84) for positioning externally of the body cavity; a tubular needle (12) having a sharp distal end (18) for penetrating the cavity wall; and means for mounting the needle in the cannula for allowing proximal movement of the needle relative to the cannula during penetration of the cavity wall, the mounting means comprising means for biasing the needle in a distal direction, to allow proximal movement of the needle against the distal bias in response to a proximal force from tissue contact at the distal end of the needle during penetration of the cavity wall. <IMAGE> |
