The Anatomy of the Horse’s Mouth: Choosing the Right Bit for Comfort and Communication

Lick and Chew Away

When it comes to horsemanship, one of the most crucial – yet often misunderstood – aspects is the bit. Selecting the right bit isn’t just about control or tradition; it’s about comfort, communication, and respecting the unique anatomy of your horse. In this post, we’ll explore the anatomy of the horse’s mouth, how different mouth and lip shapes affect bit selection, where various pressures are applied, and what you should consider to ensure your horse’s wellbeing and responsiveness.

The Basics: Anatomy of the Horse’s Mouth

To choose the right bit, it’s essential to understand what’s going on inside your horse’s mouth. Here are the key features:

• Lips: The outermost part, soft and sensitive, forming a seal around the bit.

• Bars: The toothless gap between the incisors and molars – the primary resting place for most bits. (Think of the human equivalent being the back part behind where your teeth are-that ridge area.)

• Tongue: Thick and muscular, it cushions the bit and can be sensitive to pressure.

• Palate: The roof of the mouth, which can be low or high – important for bit selection.

• Cheeks: Muscles, skin and nerves on the sides of the face, which can be affected by certain bit designs.

• Poll: The area directly behind the ears, where some bits (especially those with leverage) can exert pressure.

  
  

Mouth Shapes and Lip Types – Why They Matter

Just as people have different oral anatomies, so do horses. The shape and size of a horse’s mouth, thickness of the tongue, height of the palate, and fullness of the lips all play roles in how a bit sits and feels.

• Small Mouths & Thick Tongues: Horses with smaller oral cavities or thick tongues may find bulky bits uncomfortable. Slimmer, single-jointed or French link bits are often more suitable, avoiding palate pressure.

• High Palate: A horse with a high palate may tolerate a single-jointed bit better, as it’s less likely to press into the roof of the mouth.

• Low Palate: Horses with a low palate are more prone to discomfort from single-jointed bits; double-jointed or anatomical mouthpieces may improve comfort.

• Fleshy Lips: Full, fleshy lips can be pinched by loose ring bits or poorly fitted mouthpieces. In these cases, fixed ring or eggbutt bits, and bits with larger cheekpieces or lip guards, can prevent pinching.

• Flat Bars: Some horses have flatter bars, making them more sensitive to pressure. Softer, thicker bits distribute pressure more evenly.

Pressure Points: Where Does the Bit Act?

The type and design of a bit determine which pressure points are engaged:

• Mouth (Bars and Tongue): Most snaffle bits act directly on the bars and tongue. Thinner bits increase pressure per square centimetre, while thicker bits distribute pressure more broadly.

• Lips: Bits with loose rings or poorly fitted mouthpieces can pinch the lips. Some bits, like full cheek or eggbutt snaffles, help reduce this risk.

• Cheeks: Full cheek or D-ring bits apply gentle lateral pressure to the cheeks, useful for turning aids, especially in young or green horses.

• Poll: Leverage bits (like Pelhams and curb bits) apply pressure to the poll via the headpiece of the bridle, encouraging the horse to lower its head and flex at the poll.

• Chin Groove: Curb chains or straps, used with some leverage bits, apply pressure under the chin.

Top-Down View of where a Bit Sits in a Horses Mouth (showing the tongue, teeth and skeletal structures)

Selecting the Best Bit for Your Horse

Here are some steps and considerations for choosing the best bit:

1. Assess Your Horse’s Mouth: Ask your vet, dentist or professional bit fitter to assess your horse’s mouth anatomy. Take note of tongue thickness, palate height, lip fullness, and bar shape.

2. Measure Correctly: A bit that’s too narrow pinches, while one that’s too wide moves around too much. Most horses need a bit 1/4" wider than the measured width of their mouth.

3. Consider Materials: Stainless steel is common, but sweet iron, copper, and rubber can increase salivation and acceptance. Some horses have preferences!

4. Try Different Designs: Double-jointed bits (like the French link or lozenge) reduce nutcracker action and palate pressure, while single-jointed bits may suit some mouth shapes.

5. Prioritise Comfort: Watch for resistance, head tossing, excessive chomping, leaning, or tongue evasions – all signs the bit may be uncomfortable or inappropriate.

6. Work with a Professional: If in doubt, consult an experienced bit fitter or equine dentist to find the best match.

Check out this blog on bit fit.

Other Important Considerations

• Training Level: Young horses often benefit from gentle, simple bits with minimal pressure points. Experienced horses may require more refined aids.

• Discipline: Different disciplines have tradition and rules regarding allowable bits. Always check competition guidelines.

• Bridle Fit: Even the best bit is uncomfortable if the bridle doesn’t fit properly. Adjust cheekpieces, browband, and noseband as needed.

• Regular Dental Checks: Sharp teeth and oral pain can make any bit uncomfortable. Schedule routine dental appointments (at least annually [every 12 months or less]).

Check out this blog on bridle fit.

How a bridle and bit fit on a horse and the actions

Wrapping Up

Choosing the right bit is both a science and an art, requiring observation, empathy, and sometimes a bit (pun intended) of trial and error. By understanding your horse’s mouth anatomy, recognising where and how pressure is applied, and paying attention to your horse’s feedback, you’ll foster better communication and a happier, healthier partner in the paddock or arena. Happy riding!