The Anatomy of the Horse

• The saddle is primarily designed to fit the horse's back, and to carry the rider's weight on the strongest part of the back. The dorsal vertebrae of the horse's back rise to a ridge between the shoulder blades, forming a bond lump at the base of the neck. This area is referred to as the withers. It is a useful area in saddle fitting, as it provides a ridge to help keep the saddle in place. However, the saddle must not exert any pressure on this area as this may damage the vertebrae. Horses with particularly high withers can be difficult to fit as it is hard to get enough clearance on the saddle.
  
  

Western Saddle Construction

• A Western saddle is built onto a wooden frame called a tree. The tree has four main parts: bars, fork, seat and cantle. The bars are weight-bearing runners that sit on either side of the horse's spine to keep pressure off the vertebrae. They attach to the fork at the front of the saddle and the cantle at the rear. The area where the bars attach to the fork is called the gullet, and this provides clearance for the withers. Different saddles have different widths and heights of gullets depending on the shape of the horse.
  
  

About the Gullet

• The angle at which the bars meet the fork of the saddle determines the height and width of the gullet. Gullets sizes are measured in inches when the tree is in its raw state. Once the saddle has been built onto the tree, the measurements cannot be accurately checked as various amounts of padding are built around the gullet afterward. Gullet widths are thus referred to by the measurements of the bars underneath them; for example, a saddle with quarter horse bars would be a narrower gullet fit than one with semi-quarter horse bars.
  
  

Fitting a Saddle

• When fitting a Western saddle, the most important thing is that it distributes the rider's weight evenly and does not pinch or rub. With the rider mounted, check that there is room to get two to four finger widths between the withers and the top of the gullet. Also check that there is room to slide the flat of your hand between either side of the withers and the saddle. The saddle should be sitting squarely on the horse's back, and the rider should be able to sit with this weight evenly distributed over both seat bones rather than being tipped forward of backward.