Tag: Hoof as a Pump

Do the hooves really serve as additional hearts? Is the frog a pump?

I’ve read recently in Pollitt’s book, that the veins in the horses hoof do not have valves to stop back flow as other veins do. If this is really the case, it highlights just how important movement is to the health of the horse. It is movement that unloads and loads the foot, and it is this loading and unloading that serves as the dynamic pumping action of the foot. Without movement, there is risk of stagnation.

I’ve read more than once the frog described as a pump. The importance of a beefy frog with ground contact upon weight bearing being the hallmark of desirable, which to me meant that others were thinking of the frog as a push pump. What I understand of biology is in line with the concept of the foot serving as a pump. But what I know about engineering showed me that it’s not that the frog is a ‘push pump’ so much as it is the whole mechanism of the hoof that works as a bellows pump, and the frog serves as the bellows proper.

Moving from the left to the right: the bar, outside frog wall, central sulcus wall x 2, outside frog wall, and bar wall all work together to form the bellows.

The wall, serves as the spring mechanism upon which the expansion and contractions of the foot acts, and that returns the expanded bellows to it’s un-expanded state, when pressure is released. When the foot is weighted, both the bellows and the wall expand. When the foot is unweighted, both the bellows and the wall contract. The degree of movement is nil at the toe, directly opposite the caudal foot, and increases in amount to where it is is largest, across the heel end of the frog.

As you ponder these things, imagine what goes on inside a foot when a static shoe is nailed on to the expansion spring while the mechanism is non weight bearing, and so, contracted. Then imagine what happens to the forces put on that now fixed structure when is is weighted.