The choice ofPandSdesignations is somewhat arbitrary in heterogeneous elastic media, but becomes precise in the high‐frequency limit of ray theory. This fact is used in a radially heterogeneous isotropic medium to establish three potentials (P,S,T) with the following properties: (1) every displacement solution is represented by some (P,S,T); (2)T(r,t) is decoupled fromPandS, is a potential forSHmotion, and satisfies second‐order wave equation; and (3) the coupling ofPandSVis represented by coupled equations in potentialsPandS. At high frequencies these equations decouple (for an important class of sources) into separate second‐order wave equations forPandS. An important role, in this decoupled case, is played by the variable density. Several possibilities suggested by the generalPandSVequations are also outlined.