Calculate Path Probabilities from Markov Chain

I am working with Markov chains and I would like to be able to calculate the degree of deviation or "unprobableness" of a given path. At each state there are probabilities assigned to each other possible state. These probabilities are not normal distributions which makes standard methods for finding probability information difficult. Essentially, I would like to be able to assign a single value to each path for how far it deviated from the most probable paths.