This feature in it is because of presence of a curved headboard and footboard that is outwardly curled at each end’s top. This footboard is often found to be shorter than the headboard. History records suggest when these were used traditionally; it did have a feature imbibed in it because of which it could curl inwards as well as outwards. Those days they were known to be made of wood. The popular practice during this period was to place them in the centre of their rooms. The objective behind this was to highlight it as one of the primary pieces of furniture of that particular room. Generally, people took immense pride in showing their prized possession.
However, with passage of time, even this feature saw a change in it. Modern sleighs are well designed to pay greater emphasis to stress it more. The rationale behind doing so is to give sufficient room for comfort to its user and it normally helps in avoiding one’s head hitting on the curl. You can see the market being flooded with wide varieties of it, which is often preferred by those who want to make a style statement.