Abstract: An improved surgical cannula assembly adapted for receiving and guiding a surgical instrument having an instrument portion insertable through the cannula assembly includes two selectively interconnectable and separable cannula subassemblies. An elongated, longitudinally outer cannula subassembly includes a fluid port extending generally laterally through a portion of the outer cannula subassembly in communication with the interior of the generally hollow outer cannula subassembly. An elongated longitudinally inner cannula subassembly includes an open inner end adapted to be positioned adjacent a surgical sit. A connecting or coupling apparatus is provided for selectively interconnecting the inner and outer cannula subassemblies with one another, in order to define a so-called "full-length" cannula for receiving full-length instruments.