Palermo had the better chances, but were unable to beat a Siena side who, without a six-point penalty, would be ahead of the Rosaneri in the table.
As it is, though, Serse Cosmi's side are still four points adrift of the Sicilians, who also remain in the bottom three having played a game more than the teams above them.
Josip Ilicic tried to inspire Palermo into action, but he was fighting a lone battle in the Palermo attack having clearly been given a different script to his defensive team mates.
Fabrizio Miccoli may have seen both scripts, but after spending the first 10 minutes with the majority of his team-mates, he joined Ilicic's crusade.
He wasted a good chance in the 20th minute when he tried to lob Gianluca Pegolo, but just lifted the ball into his arms.
Siena were even more defensive and when they did venture forward, mainly with high balls into the penalty area, Ezequiel Munoz was always there to clear the danger.
Palermo attacked more in the second half, pegging Siena back inside their own half and creating better openings.
Miccoli missed the first big chance of the game in the 58th minute when he lifted the ball over Pegolo and over the bar in a one-on-one situation with the Siena goalkeeper.
Undeterred, he tried the same again with a free-kick from 20 yards, taking a long run up but then trying to lob the ball in delicately, clearing the wall, but also the bar in the 73rd minute.
Fear of losing seemed to grip both teams, but Paulo Dybala almost snatched a win for Palermo in stoppage time when, after slipping inside the area, he lifted himself up again, but saw Pegolo push his shot over.