A biopsy instrument includes a tube having a finger-like projection at one end and a canula slidably disposed in the tube. After insertion of the biopsy instrument into a tissue, the tube is displaced on the canula so that the projection passes through an aperture in the canula to sever the tissue sample...http://www.google.de/patents/US5655542?utm_source=gb-gplus-sharePatent US5655542 - Instrument and apparatus for biopsy and a method thereof
