As far as we know, only one breed standard calls for a “two-piece topline,” and that’s the fabulous Spinone Italiano.
This interesting topline consists of two segments: The first slopes slightly downward in a nearly straight line from the withers to the eleventh thoracic vertebra, while the second part rises gradually and continues into a solid and slightly convex loin without rising above the withers. This is apparent in profile as a dip in the back. Coupled with big feet, this top line gives the dog stability on rough ground with a sure-footedness and an economy in movement which helps with endurance in the field. Most certainly, where these dogs traditionally hunted was rough: The Spinone was named after a thornbush called the pino, a favorite hiding place for small game but virtually impenetrable by larger animals. Only a thick-skinned, coarse-coated dog could fight through these branches and emerge unscathed by the thorns, and the Spinone was that dog.
A true Spinone hunts very differently than any of the other pointing breeds. They trot with their heads held high, tail switching side to side and crooking this way and that into the wind. They work carefully in gun range with a modulated trot, and rarely over-run their nose. They do slow down gradually when they detect a bird, and then cautiously freeze on point. Not every Spinoni hunts in the absolute correct Spinone style, but there’s no mistaking it when it’s seen.
Insert image from the AKC website with consent