As a generalization of the normal or Gauss distribution to many dimensions we define the multinormal distribution. In statistics,  the multivariate normal (mvn) is a widely-used distribution, for instance, basket option pricing, portfolio VaR analysis. Unluckily, its cumulative distribution function (cdf) doesn't take a closed form. There are, nevertheless, amounts of techniques that numerically approximate the value of the cdf.

Here is one of such methods in M file.

http://alex.strashny.org/a/Multivariate-normal-cumulative-distribution-function-(cdf)-in-MATLAB.html
wiki(Multivariate normal distribution)