Universal seal for use with endoscopic cannula

A cannula for use in endoscopic surgery on a person through which medical instruments may be inserted, said cannula comprising:

• a tube with a distal end for insertion into a body cavity of said person, a proximal end of said tube remaining outside said person;
• insufflation port in fluid connection with said proximal end of said tube for inflating said body cavity;
• lower seal housing connected to said proximal end of said tube, said lower seal housing having housing opening in line with a cylindrical opening of said tube;
• lower seal in said lower seal housing for closing said housing opening when no instruments are inserted through said housing opening into said cylindrical opening of said tube;
• universal seal housing having an insertion port therethrough, said universal seal housing defining an annulus therein around said insertion port, said universal seal housing being connected to said lower seal housing;
• universal seal having flexible inner and outer rings, said outer ring being firmly retained at an outer portion of said annulus, said flexible inner ring being located in an inner portion of said annulus a distance inward from said outer ring but surrounding said insertion port;
• expandable central opening in said universal seal, said expandable central opening accommodating different size instruments therethrough, said flexible inner ring being movable from side to side in said annulus during side to side movement of said medical instruments while inserted in said cannula, upper and lower surfaces of said annulus rubbing against said inner ring.