When cold and in the non-coated state, an aerodynamic profile defining an arm of a structural casing of a turbine having a central hub and a shroud is substantially identical to a nominal profile determined by Cartesian coordinates X,Y,Zadim given in Table 1, in which the coordinate Zadim is a quotient D/H where D is a distance of a point under consideration from a first reference plane P0 situated at a base of the nominal profile, and H is a height of said nominal profile measured from the first reference plane to a second reference plane P1. The measurements D and H are taken radially relative to an axial direction of the turbine, while the X coordinate is measured in the axial direction of the turbine.