A patient support apparatus having a base, a litter frame, an elevation mechanism interconnecting the base to the litter frame and being configured to effect changes in elevation of the litter frame relative to the base. The litter frame includes a pair of laterally spaced and longitudinally extending support rails and a plurality of laterally extending support rails interconnecting the longitudinally extending support rails so that the litter frame has a rectangular configuration. Selected ones of the laterally extending support rails are mounted to the elevation mechanism. On the aforesaid litter frame there is mounted various modules, namely, (1) a patient support deck, (2) a set of lateral edge siderails, (3) a holder for bottled gas, (4) an attendant work surface, oriented beneath the head section when the head section is in a horizontal position, (5) a seat, thigh and foot section assembly, and (6) a head section having manipulatable controls thereon supportingly secured to the litter frame separately from the seat, thigh and foot section assembly.