A horse should look functionally correct, even to an untrained eye. The length of neck should be considered long when compared to the length of back and hip. It should tie desireably into a well laid back shoulder. (This is to increase the horse's balance, and also allow for greater shock absorbtion.

Regardless of the use, a "short" back is sought after in a performance horse. The back is measured from the point from the slope of shoulder to the point of the hip as shown on the skeleton below.

The hip should be long and rather flat, if a usable hind end is desired. (this is especially true when selecting for a hunter or dressage prospect, but less true when selecting for a reigning prospect.)

So, now that you've read this, which one of these two stallions is the better balanced individual?

A

or

B