10/10/2026
🧠 𝗛𝗢𝗥𝗦𝗘𝗦 𝗗𝗢 𝗚𝗘𝗧 𝗛𝗘𝗔𝗗𝗔𝗖𝗛𝗘𝗦!! - 𝗣𝗔𝗥𝗧 𝟮 🐴 𝗪𝗛𝗔𝗧 𝗜𝗦 𝗬𝗢𝗨𝗥 𝗛𝗢𝗥𝗦𝗘'𝗦 𝗧𝗔𝗜𝗟 𝗧𝗘𝗟𝗟𝗜𝗡𝗚 𝗬𝗢𝗨?
Now, you're probably wondering what on earth your horse's tail has to do with its head!
Quite a lot anatomically, although perhaps not in the way you're imagining.
In Part 1, we explored the meninges, the dura mater, the spinal cord and the remarkable anatomical relationships around the poll and upper cervical spine.
But those structures don't simply stop at the neck.
So today, let's go to the opposite end of the horse.
Because one thing well worth paying attention to is how a horse carries its tail.
Does it consistently sit to the left?
Or perhaps to the right?
Does it change when the horse moves, particularly in trot?
Does it become more obvious on a circle, or when ridden?
And have you always assumed that's simply how your horse carries its tail?
👀 THERE'S SOME VERY INTERESTING RESEARCH ABOUT THAT!
A study by Hibbs, Jarvis and Dyson, published in Equine Veterinary Education (2021), investigated crooked tail carriage in 690 sports horses.
🐴 32.5% of lame horses carried their tails crookedly, compared with just 5.3% of non-lame horses.
Crooked tail carriage was also significantly associated with:
• Hindlimb lameness
• Sacroiliac joint region pain
• Increased thoracolumbar epaxial muscle tension
Of the lame horses with crooked tail carriage, 60.9% carried their tails to the LEFT.
But the direction of tail deviation did NOT correlate with the side of the predominantly lame limb.
Read that again!
Just because a horse carries its tail to the left doesn't mean the left hindlimb is the source of the problem.
And this is where an osteopathic perspective comes in.
🦴 LET'S TALK ABOUT THE SACRUM
The sacrum sits between the two ilia, forming the sacroiliac joints. I like to describe it as the sacral wedge within the pelvic ring: the crucial mechanical link between the hindquarters and the vertebral column.
The equine sacroiliac joint is a strong, relatively stiff joint with only small ranges of movement. But small doesn't mean unimportant.
In the osteopathic assessment model, the sacrum is assessed for patterns of nutation, counternutation and rotation around oblique axes, and for how these relate to the lumbar spine, the ilia and the transfer of forces from the hindlimbs.
These aren't measurements of large bony displacements. They're a way of describing and organising what is found on hands-on assessment: where movement feels free, where it feels restricted, and how that differs between sides.
So an osteopathic assessment looks beyond whether the pelvis appears higher on one side. It considers the relationship between the sacrum and both ilia, the quality of movement available, and the adaptations through the lumbar spine.
Because a sacral restriction is not necessarily a straightforward left-sided or right-sided problem.
Within this model, a particular sacral pattern may be associated with lumbar side-bending in one direction and rotation in another, and with a preference towards nutation or counternutation.
And the tail❓️
The tail is mechanically connected to this entire region.
The sacrum articulates with the first caudal vertebra, and the tail continues as a series of caudal vertebrae, surrounded by muscles, ligaments, fascia, nerves and blood vessels.
The sacrocaudalis dorsalis and ventralis muscles, which lift, lower and hold the tail, are supplied by caudal nerves arising from the cauda equina.
So tail position is influenced by much more than the tail itself.
When a horse consistently carries its tail to one side, the question is WHY.❓️
❓️❓️
Is there a change in how the sacrum and ilia are moving?
What's happening through the lumbosacral junction?
Is there increased tension through the epaxial musculature?
Does the horse have a restricted or painful hindlimb?
Is the tail deviation present at rest, or only when the horse moves?
Does it change when the horse bends, turns or carries a rider?
🟢 In my own assessments, a clamped, guarded or one-sided tail very often goes hand in hand with sacral findings. It's one of the most consistent patterns I see.
(If you've missed them, have a look back at my SI joint posts, and there are more of those to come!)
🟰 But the direction of the tail alone doesn't identify which sacral pattern is present.
Even within the osteopathic model, a tail carried to the right can belong to more than one sacral pattern. Tail height, the lumbar spine and the position of the tubera all need assessing too.
That's something to investigate through hands-on assessment, not something to diagnose by looking at the tail.
🔍 WHAT THE RESEARCH DID, AND DIDN'T, SHOW
The study found associations between crooked tail carriage, sacroiliac region pain and increased thoracolumbar muscle tension.
It didn't investigate osteopathic sacral patterns, or whether a particular pattern produces a particular direction of tail deviation.
That's an important distinction.
But it raises some great questions.
If the tail is consistently carried to one side, what adaptations are happening through the sacrum and lumbar spine?
And could different patterns produce a similar outward appearance?
Two horses can show the same crooked tail carriage with very different underlying problems.
The visible adaptation is not necessarily the primary problem.
🧠 SO WHAT HAS ALL THIS GOT TO DO WITH THE HEAD?
Back to the anatomy from Part 1.
The spinal cord runs within the vertebral canal, surrounded by three protective meningeal layers:
• Dura mater
• Arachnoid mater
• Pia mater
These layers are continuous along the spinal cord and with the coverings of the brain.
But the spinal cord itself doesn't extend down the tail.
Towards its caudal end, it tapers into the conus medullaris. (The tapered, lower-most functional end of the spinal cord itself).
In the horse, this usually sits somewhere around the cranial sacral region, around S1–S2, with individual variation. As anyone who has been in a dissection room knows, nothing is exact!
Beyond this point, the nerve roots continue caudally within the vertebral canal, forming the cauda equina.
These nerve roots supply structures including the pelvic region, perineum and tail.
And then theres the FILUM TERMINALE.
Its internal portion, the filum terminale internum, continues from the conus medullaris within the dural sac.
The more distal portion, the filum terminale externum, is wrapped in dura and anchors onto the caudal (tail) vertebrae.
So part of this system genuinely reaches into the tail.
And remember Part 1?
The dura surrounding the spinal cord is continuous cranially with the dura surrounding the brain.🔶️
The caudal spinal region and the cranial cavity are not anatomically isolated from one another. They belong to one continuous neurological and meningeal system.
That doesn't mean a crooked tail is pulling on the brain, or that a sacral restriction automatically causes a headache.
But it does mean the head and sacrum shouldn't be thought of as completely unrelated.
The anatomical continuity is real.
What remains to be established scientifically is how particular restrictions might influence that system in the living horse.
That's what makes osteopathic assessment so interesting: looking at relationships, adaptations and how the whole horse functions, rather than chasing the area where a symptom happens to appear.
🐴 SO WHAT MIGHT YOU NOTICE IN YOUR OWN HORSE?
Perhaps your horse:
• Consistently carries its tail to one side
• Changes tail position between the left and right reins
• Carries its tail differently when ridden compared with moving freely
• Has difficulty maintaining bend in one direction
• Struggles with transitions or engaging the hindquarters
• Shows tension through the lumbar region
• Has uneven or altered pelvic movement
• Has been diagnosed with hindlimb lameness or sacroiliac region pain
These signs don't all mean the same thing, and none on its own identifies a specific sacral problem.
But they're observations worth paying attention to.
⚠️ And if tail carriage changes suddenly, particularly alongside pain, weakness, altered sensation, or difficulty urinating or passing droppings, call your vet.
THE IMPORTANT QUESTION ISN'T SIMPLY WHICH WAY THE TAIL POINTS.
It's WHY the horse is carrying it that way.
And what else is happening throughout the body that might help explain it.
The horse with a crooked tail may be
showing a much larger adaptation.
The horse that's sensitive around the head may have other areas worth considering.
One doesn't automatically cause the other. But neither should be assessed in complete isolation.
That's the point of this whole series.
The horse is one interconnected animal.
And sometimes the most useful clues are found a long way from where we first started looking.
🐴 NEXT TIME YOU WATCH YOUR HORSE WALK OR TROT AWAY, LOOK AT ITS TAIL.
Does it sit centrally?
Does it consistently deviate?
Does it change with movement?
You might start noticing something you've never really paid attention to before.
🎓 WANT TO UNDERSTAND WHAT YOU'RE FEELING WHEN YOU ASSESS THE SACRUM AND SI JOINTS?
I'm currently developing my new Equine SI Joint Course, taking the anatomy, biomechanics, assessment and osteopathic relationships we've been discussing to a much deeper level.
This isn't about memorising a list of dysfunctions. It's about developing your understanding of the relationships between the sacrum, ilia, lumbar spine and the rest of the horse, and learning to interpret what you're finding through your hands.
📩 Applications will open exclusively through my email list.
If you'd like the opportunity to apply, make sure you're subscribed.
✌️🫶👇https://www.helenthornton.com/email-updates
Research: Hibbs, K. C., Jarvis, G. E. & Dyson, S. J. (2021). Crooked tail carriage in horses: Increased prevalence in lame horses and those with thoracolumbar epaxial muscle tension or sacroiliac joint region pain. Equine Veterinary Education, 33(7), 368–375.
https://doi.org/10.1111/eve.13316
Before posting, check the 690 / 32.5% / 5.3% / 60.9% figures against the paper's abstract.
Veterian Key. (2017, September 27). Nervous system. Veterian Key. https://veteriankey.com/nervous-system-2/
