The measurement of the local curvature of arbitrary discrete 3-D medical images is complicated by the difficulties of defining a local neighborhood and then mapping the surface of the neighborhood onto the unit square as a way to unambiguously define a parameterization. Five practical methods are presented for deriving one or more measures of curvature about a point on an arbitrary discretized surface. The first 3 methods approximate the surface patch using continuous biquadratics while the next 2 methods obtain the curvature directly from the discrete data points on the surface which define the neighborhood. The 5 methods are compared in computational complexity accuracy and robustness in the presence of a noisy surface. 1.