Saddle fitting advice (Part 2) Before Ken even gets his saddles out of the car he gives the horse a thorough check by feeling along his back and monitoring the reaction. The application of gentle but firm pressure enables him to pinpoint any sensitive areas and assess the horse's muscle tone.     Ken runs the tips of his fingers firmly along each side of the horse's spine.     Pressing on the sacroiliac area will show up any problems in these muscles.   Ken checks the longissimus dorsi,  the main weight-bearing muscles on each side of the spine in the same way.     The trapezius muscle lies across the wither and can be damaged by an ill-fitting saddle.   With the horse standing square, Ken stands directly behind him and checks whether the shoulders are the same size. Uneven shoulders can be a sign of muscle wastage or uneven muscle development.   He then sees the horse walking away from him so he can check the movement of the quarters and see how level the haunches are.