Bits and the anatomy of a horse’s mouth

Many people choose a bit because

  1. It’s already in their tack box
  2. Everyone else at the barn rides in one
  3. The bit doesn’t matter — it’s the rider’s hands that matter, or
  4. The horse was ridden in the bit forever, so why change?

Hey, those are the criteria I used for selecting bits for years. My first couple of horses were easy: I rode them in either a loose ring single jointed snaffle or a full cheek snaffle (generally with a single joint).  It took a horse with who had a strong opinion about bitting (Kroni) to make me think about the anatomy of a horse’s mouth — and why some horses do better in a certain type of bit over another. And another horse who has more get up and go than whoa (Freedom) to make me start to think about the need for control and lightness.

I’ve written plenty in this blog about riding bitless — ultimately, that proved to be the best solution for Kroni — but I’m not against bits. They offer the most direct form of communication and that communication can be very subtle. With a horse like Freedom, riding bitless, at least in the hunt field, simply isn’t an option. I suppose that I could use a hackamore, but those exert a tremendous amount of pressure on the horse’s very sensitive nose. I needed to find a bit that could still catch his attention during the adrenalin rush of galloping in the hunt field but which wasn’t so severe that he would curl up behind the bit and not accept contact.

Let’s start with the way that bits work in a horse’s mouth:

This diagram shows the anatomy of a horse's mouth. The areas where a bit can exert pressure include the tongue, the corners of the mouth, the "bars", teeth, palate and chin groove. Which bit you choose depends on how your horse responds to the pressure.

When selecting a bit you need to take into consideration the anatomy of that horse’s mouth. Kroni had a thick tongue and a low palate. This made many bits, especially single jointed bits, uncomfortable for him. He did far better in a mullen mouth bit (no joint) that wasn’t too thick. While thicker bits are generally considered to be milder (in theory they disperse the area over which the horse feels the pressure of the bit) and thin bits to be severe, for him, the thicker bits just didn’t fit well in his mouth and the joint (especially the single joint) was hitting him in the roof of his mouth. Ouch! He seemed more comfortable in double jointed bit designs but even those made him very fussy.

I’ll look more specifically at some of these bits in future posts.

More resources on bits and the anatomy of the horse’s mouth.

Radiographic study of bit position within the horse’s oral cavity, J. Manfredi, HM Clayton and D. Rosenstein, Michigan State University.

Bit by Bit, the Whys and Hows of Bit Science, Emily Esterson

3 thoughts on “Bits and the anatomy of a horse’s mouth

  1. Oooh this is GOOD. Keep it coming. I love this stuff. I almost developed an aversion to bits because of my own shortcomings in understanding them and their relation to each of my horses’ mouths. I can learn from this!
    Thanks.

  2. I find that a full cheek is my “go-to” bit on a new horse, until I find what they like. Before I bought my mare who I lost recently, she was ridden in an incredibly thick egg-butt, which didn’t fit her mouth at all (she had a low palate). When I had the dentist out, he gave me some ideas of bits to try, but she hated every bit I ever had in her mouth but the egg-butt. Some horses just get stuck in their ways, I guess.

  3. This is a much needed article on an important topic. I also followed what I learned for a long time, not seeing the need to investigate much else until a horse pushed my nose right into the topic, so to speak. Then started investigating alternatives, bitless and finally the leather bit.
    I now almost exclusively use a leather snaffle and a leather pelham. Also still have a full cheek JP snaffle (doesn’t poke the horse’s palate). Everything else is retired from day-to-day use… Bitless is also wonderful, but I personally prefer a gentle bit. (Leather is great in the winter in Wisconsin!)

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