as speculum member 135 a and speculum member 135 b the speculum members 135 collectively form a conically shaped speculum when positioned adjacent one another as in fig4 the speculum members 135 have walls that meet along a central plane that intersects with the central axis 410 of the conical speculum assembly 110 the central plane is perpendicular to a plane defined by fig4 the speculum members 135 can mate with one another along the adjacent walls such as in an interdigitating manner in order to stabilize the speculum members 135 relative to one another during use of the system 100 with reference still to fig4 one or more protruding flanges or ribs 405 are interspersed along the speculum members from the proximal rim 140 to the distal edge 145 the illustrated embodiment includes three annular ribs 405 although it should be appreciated that additional ribs 405 or less ribs 405 can be used the ribs 405 extend radially outward relative to the central axis 410 of the speculum assembly 110 each rib 405 has a bottom surface 415 and an upper surface 420 in the illustrated embodiment the bottom surface 415 of each rib 405 is upwardly sloped the upper surface 420 of each rib 405 is horizontal the upwardly sloped bottom surfaces 415 assist in displacement of tissue upon insertion of the system 100 into tissue and also assist in rotation of the speculum it should be appreciated that the ribs 405 can have other shapes fig5 a 5g are diagrams of an exemplary tissue access and channel formation method that uses the system shown in fig1 in an exemplary embodiment.