A cannula (10) receives surgical instruments (120) for performing a surgical procedure on a body (130). The cannula (10) comprises a tube structure (12) defining a passage (16) through which the surgical instruments (120) are inserted into the body (130). The tube structure (12) has a proximal end (20)...http://www.google.ca/patents/US20040078051?utm_source=gb-gplus-sharePatent US20040078051 - Cannula for receiving surgical instruments
