  In his calculation of the spacetime volume of a small Alexandrov interval in
4 dimensions Myrheim introduced a term which he referred to as a surface
integral [1]. The evaluation of this term has remained opaque and led
subsequent authors to evaluate the volume using other techniques [2]. It is the
purpose of this work to demystify this integral. We point out that it arises
from the difference in the flat spacetime volumes of the curved and flat
spacetime intervals. An explicit evaluation using first order degenerate
perturbation theory shows that it adds a dimension independent factor to the
flat spacetime volume as the lowest order correction. Our analysis admits a
simple extension to a more general class of integrals over the same domain.
Using a combination of techniques we also find that the next order correction
to the volume vanishes.
