Indexing cannula support mechanism

摘要

A tissue sampling instrument for use with various needle gauges to extract tissue samples includes a support structure, preferably rotatable, including a plurality of needle support seats having different seat dimensions corresponding to respective different needle circumferences. The seats are arranged on the support structure to enable selective access and positioning of each seat in order to selectively support the corresponding needle circumference thereon and ensure accurate linear longitudinal motion of the needle against the selected seat in the tissue sampling procedure. The preferred rotatable support structure can be mounted on an end wall of the body of the instrument so that the supported needle projects from the end wall.