The Well Balanced Equine

04/30/2026

04/30/2026

04/18/2026

Believe what your horse tells you.

Whether they are shouting or whispering or somewhere in between.

I am half way through a two day dissection and this really struck me. It might seem like a given, a no- brainer. But for many it is not. 

Can you train/correct an issue away with relative ease? Great. Does it take concerted effort and does that issue keep slipping back in? It is not a training issue. Or a behavior issue.

If we are going to partake in the incredible privilege of sitting on our horses backs, I do believe that we need to help them carry themselves in the most biomechanically correct way that will help ensure their long-term health.

Horses are simply not built to carry us. I think we forget this. A lot.

Part of that process is allowing them to carry themselves in such a way that works for each individual horse. There are no cookie cutters in true horsemanship. There are no guarantees that your lovely fill-in-the-blank prospect actually has the ability to fulfill that particular purpose.

We have to listen and allow. Be willing to pivot, be willing to substitute our personal goals with, when they don’t align, what our horse actually needs, what our horse is actually capable of doing without being crammed into a frame, drilled into the ground, strapped into place.

Mostly, we need to slow down and just listen and let the horses truth be our truth, too.



04/15/2026

The Vagus Nerve in Horses

Where it runs, what it does, its relationship to fascia, and how to influence it through bodywork and movement

What the Vagus Nerve Is

The Vagus nerve is the primary nerve of the parasympathetic system—the part of the nervous system responsible for rest, recovery, digestion, and regulation.

More than just a motor nerve, roughly 80% of its fibers are sensory, meaning it is constantly carrying information from the body back to the brain. This makes it highly dependent on the state of the tissues it passes through and innervates.

Where It Runs in the Horse

The vagus nerve originates in the brainstem and travels:
• Through the poll and upper cervical region
• Down the neck within the carotid sheath
• Through the thoracic inlet
• Into the thorax (heart and lungs)
• Into the abdomen (digestive organs)

This pathway places it in close relationship with:
• The base of the neck
• The thoracic sling
• The ribcage and sternum
• The diaphragm
• The visceral space

These are all regions where posture, tension, and fascial restriction can influence its function.

What It Does

The vagus nerve regulates core physiological and behavioral functions:
• Heart rate and variability
• Breathing rhythm and depth
• Digestive motility and efficiency
• Inflammatory response
• Ability to down-regulate after stress

In practical terms, it reflects the horse’s ability to shift out of a protective, sympathetic state into a more regulated, adaptive one.

The Fascia Relationship

The vagus nerve exists within the body and is strongly influenced by Fascia.

1. Mechanical Environment

Fascial tension in the neck, thoracic inlet, and ribcage can alter the pressure and mobility of the tissues surrounding vagal pathways.

2. Visceral Fascia

The organs innervated by the vagus are suspended and organized by fascial layers. These layers must be able to glide and deform for normal function.

3. Sensory Input

Fascia is highly innervated and constantly feeding information to the nervous system. Poor tissue quality increases “noise” and can bias the system toward protection.

4. Fluid and Hydration

Healthy fascia supports fluid movement and adaptability. Stiff or dehydrated tissue alters the internal environment the nervous system is reading.

How It Shows Up in the Horse

A horse with better vagal tone tends to show:
• A softer, more mobile neck, jaw and chest
• More regular breathing patterns
• Improved digestion
• Greater ability to settle after stress
• Willingness to engage without bracing or internalizing

A horse with reduced vagal influence may present as:
• Tight through the poll and base of neck
• Restricted ribcage movement
• Shallow or inconsistent breathing
• Digestive sensitivity
• Reactive or guarded behavior

How to Positively Influence It

You are not directly “stimulating” the vagus nerve. You are improving the conditions it depends on.

1. Restore Comfortable Range of Motion

Work the horse through pain-free, controlled movement:
• Lateral bending
• Gentle flexion and extension
• Ribcage mobilization

This improves sensory input and reduces protective guarding.

2. Improve Ribcage and Diaphragm Function

The vagus nerve has strong influence over heart and lungs, which are mechanically tied to the ribcage and diaphragm.
• Encourage rib mobility
• Address sternum and intercostal restrictions
• Support full, rhythmic breathing

3. Address Key Fascial Transitions

Focus on areas where mechanical tension concentrates:
• Poll and upper cervical region
• Base of the neck and thoracic inlet
• Sternum and ventral thorax
• Diaphragm attachments
• Thoracic sling and back muscle

The goal is to restore comfort, glide and adaptability.

4. Use Slow, Sustained Contact

Gentle, consistent input allows the nervous system to shift out of protection.
• Avoid fast, aggressive techniques
• Allow time for the tissue and system to respond
• Work with the horse, not “on” them

5. Include Jaw, Tongue, and Hyoid Work

These structures have strong neurological connections and often influence overall tone.
• Releasing tension here can affect the entire system
• Changes are often reflected in breathing and posture
• This is an extremely delicate and somewhat invasive area that must be addressed carefully and considerably.

6. Reduce Background Stressors

Pain, poor posture, poor nutrition or other environmental stressors and compensatory movement patterns continuously feed the nervous system.
• Improve posture and load distribution
• Reevaluate environmental factors
• Address chronic restrictions
• Support movement quality under saddle and in-hand

The Practical Takeaway

The vagus nerve reflects the internal state of the horse. It is shaped by:
• Tissue quality
• Movement variability
• Mechanical pressure and tension
• The clarity of sensory input
• Emotional balance

When fascia moves well, breath is unrestricted, and movement is organized, the nervous system receives a clearer, safer signal.

That is what improves regulation.

You improve the body the nerve lives in, and the nervous system follows.

https://koperequine.com/how-prosix-affects-posture-movement-and-stress-in-horses/

04/06/2026

Serratus dorsalis
Recently, I was asked about the serratus dorsalis, and I realised it’s one of those muscles we all “know” from books, but rarely really look at in the body.

If we stay with the textbook first, the serratus dorsalis is described as a segmental muscle with multiple semi-separated bellies. It originates from the thoracolumbar fascia and attaches to the ribs, sitting under the latissimus dorsi and covered by the superficial layer of the thoracolumbar fascia. It is divided into a cranial and caudal part, both arising from the deeper layer of the thoracolumbar fascia, but with different fibre directions and rib attachments. The cranial part runs caudoventrally and attaches roughly from the 5th to the 11th or 12th rib, while the caudal part runs cranioventrally and attaches to the last ribs. Functionally, both are described as respiratory muscles—the cranial part assisting inspiration by drawing the ribs forward and outward, and the caudal part assisting expiration by drawing them back. Innervation comes from the thoracic spinal nerves.

All good, all neat, all very logical.

But when you actually look at it in the body, things start to feel a bit less simple.

Across multiple dissections I keep seeing the same pattern. The cranial part has noticeably shorter fibres, but more interesting is that the first two or three bellies are not behaving like the rest of the muscle. They are partially separated, and their aponeurosis blends very specifically with the cranial extension of the thoracolumbar fascia—the structure often referred to as the dorsoscapular ligament. And then there is another detail that keeps catching my eye: those same cranial bellies attach to ribs 5 to 8… exactly the same ribs as the serratus ventralis thoracis.

That makes me pause a bit.

Because now we are no longer just in a “respiratory muscle sitting on the ribs” situation. We are right in the middle of the thoracic sling, in a region where the limb is suspended from the trunk purely by soft tissue—the synsarcosis. And this area is anything but simple.

Under the scapula, the fascia is not just a wrapping layer. It is a highly organised system where collagenous and elastic components transition into each other. You can see it clearly in dissection—the tissue changes character depending on what is needed. Support in one place, compliance in another, but always continuity.

The dorsoscapular ligament, as the cranial continuation of the thoracolumbar fascia, reflects this very well. It is not just a dense sheet. It has a collagenous part, but also elastic components that extend laterally toward the medial surface of the scapula and interdigitate with the serratus ventralis thoracis. When you remove the muscle fibres of the serratus ventralis, those elastic laminae become visible, and you start to see that this is not just “a muscle on a rib”, but a layered system. There is also a continuation back into more collagenous tissue attaching to the cranial ribs, forming what feels like an inner fascial envelope for the serratus ventralis.

And the serratus ventralis itself sits right between these layers. Short fibres, enclosed, supported from both sides. It starts to look much more like a structure designed for controlled load transfer and fine adjustment rather than just simple contraction.

So when I go back to the serratus dorsalis cranialis, especially those first few bellies blending into this system and sharing rib attachments with the serratus ventralis, I can’t help but wonder if calling it purely a respiratory muscle is just… incomplete.

I don’t have an answer for that yet, and I haven’t found anything in the literature that clearly supports another role, so this remains an observation, not a conclusion.

But this is exactly why I love dissection. Because even though we are separating structures, it is the best way to start understanding their continuity. And in this region especially, the body doesn’t behave in isolated parts—it behaves as a connected, adaptive system.