What serves as a cushion for the hoof and helps circulate blood through the leg?

The frog is an important structure within the horse's hoof that serves multiple functions, one of which is acting as a cushion. Located on the underside of the hoof, the frog is a triangular, rubbery pad that helps absorb shock when the horse moves. This cushioning effect is crucial not only for the horse's comfort but also for the proper functioning of the legs and joints.

Additionally, the frog plays a vital role in facilitating blood circulation through the horse's leg. When the horse walks or runs, the frog compresses and expands, which helps pump blood back up the leg and towards the heart. This action is particularly important because the horse's hoof acts like a pump, aiding in the circulation of blood while also supporting the weight of the animal.

The other structures mentioned, such as the heel bulbs, buttress, and coronary band, have their own specific functions but do not combine the cushioning and circulation roles to the extent that the frog does.