The seat must be wide enough to accommodate the rider's offside thigh as well as buttocks. A sidesaddle is comparatively flat from front to rear. Many have a small curved pommel and a long, raised cantle on the off side to support the offside thigh and to help riders keep their spine squared on the horse's back. On some designs, the seat of the sidesaddle is angled away from the side on which the legs lie to help the weight of the rider remain centered over the horse's back. The near-side flap is commonly cut forward to keep the rider's right leg and foot from touching the horse's left shoulder. The girthing of an English sidesaddle is usually a three-buckle system, with a usual full-length girth and an additional balancing girth. The stirrup of a sidesaddle is much shorter than in a conventional saddle, so that the rider's knee is placed close to the leaping horn, and it buckles midway down the leather rather than close to the tree.