A side extender assembly for providing additional width to a surgical table. The side extender assembly includes an extender frame having at least one support leg integral therewith. The support leg includes a recess for receiving a side rail of the surgical table, and a tang defining an upper portion of the recess which extends over and behind the side rail in a mounted position. A stud is threadably engaged with the support leg for engaging a lower edge of the side rail to wedge the support leg into firm engagement with the side rail in the mounted position. A thumb screw is threadably engaged with the support leg for contacting the table frame to counteract a moment force applied against the side extender assembly by a patient. The extender frame includes an x-ray passage for permitting an x-ray panel to be inserted through the side extender assembly to a location within a frame of the surgical table.