Matthew Bartlett, 28, was called before Chief Judge Belvin Perry near the end of Thursday's proceedings in the Casey Anthony murder trial and shown courtroom camera pictures of himself making the gesture at prosecuting attorney Jeff Ashton, WOFL-TV, Orlando, reported Friday.
Perry cited a sign at the entrance of the courtroom stating "any gesture, facial expression or audible comment showing approval or disapproval during a court proceeding is absolutely prohibited."
"I'm truly sorry for doing this. This was something stupid, and I'm not sure why I even did it," Bartlett said.
Perry sentenced Bartlett to six days in jail along with a $400 fine and "applicable statutory court costs."
Bartlett has the opportunity to appeal the ruling and was informed of his right to a court-appointed attorney.