A surgical table extension features a patient support structure, a large area base, and a support leg. A first joint having at least two degrees of freedom is located between the patient support structure and the support leg. A second joint also having at least two degrees of freedom is located between the base and the support leg. There is a stop limiting the range of motion of the support leg such that a portion of the base area is constrained to be below the first joint irrespective of the position of the base.