Of the nature of an interjection in either sense; interjectionary.
The Century Dictionary (Public Domain)
Use "interjectory" in a sentence
"Over at Media Matters, Eric Boehlert calls out the media for covering Rep. Joe Wilson's interjectory fireworks during President Obama's address to a joint session ..."
"GOOD point, in my opinion … and I appreciate the second interjectory paragraph too, but then in the third paragraph below, you correctly return to discuss frame dependency as a possible reason and explanation for this conundrum …."
"The film is shot using "Automovision", a computer program that randomly selects the camera angles, cuts and movements, and Lars himself makes bizarre interjectory comments throughout the film."