Bodywork

Meet Spinalis, the Forgotten Muscle in Saddle Fitting

December 20, 2016 by Jane @ THB 43 Comments

It’s barely mentioned in saddle fit or anatomy books, yet the muscle Spinalis cervicis can hugely impact on the spinal health and movement of the horse, particularly with poor tack fit.

Meet muscle Spinalis cervicis et thoracis, a far more important muscle than is generally realized. As a deep muscle, it’s influential in mobilizing and stabilizing that hidden area of the spine at the base of the neck, the cervico-thoracic junction, deep between the scapulae.

Where to Find this Muscle

As part of the deeper musculature, Spinalis is as hidden in books as it is in life. Usually, it’s a single entry in the index.

At best, it has no more than a bit part in anatomical illustrations, usually as a small triangular area at the base of the withers. This is also where we can palpate it.

The reality is quite a bit more interesting. It’s actually a muscle of three parts – dorsalis, thoracis and cervicis. These names denote its many insertions, for it links the spinous processes of the lumbar, thoracic and cervical vertebrae.

Further back along the spine, it lies medially to Longissimus dorsi, and in fact integrates with this larger, better known muscle, attaching to the processes of the lumbar and thoracic vertebrae.

When it reaches the withers, it becomes more independent, attaching to the processes of the first half dozen thoracic vertebrae (T1-T6). Here, the cervical and thoracic portions overlap and integrate to share a common attachment. (The part we palpate, at the base of the withers, is the thoracic section.)

Heading into the neck, as Spinalis cervicis, it attches to the last 4 or 5 cervical vertebrae (C3/C4-C7). Only the lamellar portion of the nuchal ligament runs deeper than this muscle.

Its integration with other muscles is complex, and its close relationship with Longissimus dorsi partially explains why it doesn’t get much consideration as a muscle in its own right.

It is the more independent section, Spinalis cervicis, between withers and neck, that we are interested in, although its influence is present along the entire spine.

© All text copyright of the author, Jane Clothier, https://thehorsesback.com.

What Does Spinalis Do?

In his 1980s’ Guide to Lameness videos, Dr. James Rooney, first director of the Gluck Equine Research Center, University of Kentucky, referred to Spinalis as part of the suspension bridge of muscles supporting the spine (Longissimus dorsi achoring from the lumbosacral vertebrae, Spinalis thoracis et dorsalis from the upper thoracics). He also refers to this extensively in The Lame Horse (1988).

In fact, the suspension bridge analogy only really makes sense if Spinalis dorsi is considered.

Spinalis cervicis is usually credited with a role in turning the head to left to right, and raising the head.

Older texts, such as Bradley’s 1922 veterinary dissection guide, Topographical Anatomy of the Horse, mention its role in stabilizing the spine.

This creates a point of interest. Given that the nuchal ligament (lamellar portion) doesn’t attach to C6 and frequently only weakly with C5 (see the findings of anatomist Sharon May-Davis, in this earlier article ), Spinalis cervicis suddenly appears pretty important in stabilizing and lifting the base of the neck, particularly as it does so at the point of greatest lateral bending.

Spinalis and Poor Saddle Fit

Anyone who has been involved in close examination of the horse’s back will recognize Spinalis thoracis where it surfaces close to the skin, on either side of the withers.

When a horse has been ridden in an overly tight saddle, this small area of muscle can become pretty hypertrophic – raised and hardened. Typically, the neighbouring muscles are atrophied. When Spinalis is palpated, the horse often gives an intense pain response, flinching down and raising the head.

What often happens is this. An overtight saddle fits over the base of the withers like a clothes peg, pinching Trapezius thoracis and Longissimus dorsi. However, it frequently misses Spinalis thoracis where it surfaces, wholly or partially within the gullet space. Often, the muscle is partially affected.

It’s as if the neighbouring muscles are under lockdown. Free movement of the shoulder is restricted and the horse’s ability to bear weight efficiently while moving is impeded. In response to the surrounding restriction and its own limitation, this muscle starts to overwork.

Result? The horse, which was probably already moving with an incorrect posture, hollows its back even further, shortening the neck and raising its head. As this becomes even more of a biomechanical necessity, all the muscles work even harder to maintain this ability to move, despite the compromised biomechanics.

Working harder and compensating for its neighbours, Spinalis becomes hypertrophic. It is doing what it was designed to do, but it’s now overdoing it and failing to release. We now have a rather nasty vicious circle.

Here, Spinalis thoracis stands out due to atrophy of the surrounding musculature. In this TB, a clearly audible adjustment occurred in the C4-C5 area after the muscle was addressed.

The Inverted Posture and Asymmetry

Of course, saddle fit is not the only cause of an inverted posture. However, any horse that holds its head and neck high for natural or unnatural reasons is more vulnerable to saddle fit issues, thus starting a cascade effect of problems.

Are there further effects of this hypertrophy? Consider the connections.

When saddles are too tight, they’re often tighter on one side than the other. This can be due to existing asymmetry in the horse, such as uneven shoulders, uneven hindquarters, scoliosis, etc.
On the side with greater restriction, the muscle becomes more more hypertrophic.
With its attachment to the spinous processes of the lower cervical vertebrae, there is an unequal muscular tension affecting the spine.
Without inherent stability, the neck and head are constantly being pulled more to one side than the other, with the lower curve of the spine also affected.
Base of neck asymmetry affects the rest of the spine in both directions and compromises the horses ability to work with straightness or elevation.
There is also asymmetric loading into the forefeet.
We haven’t even started looking at neurological effects…

This isn’t speculation. I have seen this pattern in horses I’ve worked on, many times over.

So, How Do We Help?

In working with saddle fit problems, the saddle refit may be enough to help the horse, if the riding is appropriate to restoring correct carriage and movement. Obviously, the horse’s musculoskeletal system is complex and no muscle can be considered in isolation. As other muscles are addressed through therapeutic training approaches, with correct lateral and vertical flexion achieved, M. spinalis will be lengthened along with the surrounding musculature.

I hold with a restorative approach:

Refit the saddle, preferably with the help of a trained professional,
Remedial bodywork, to support recovery from the physical damage,
Rest the horse, to enable healing of damaged tissue and lowering of inflammation, and
Rehabilitate the horse, through the appropriate correct training that elevates the upper thoracics while improving lateral mobility.

This is particularly important where saddle fit has been a major contributor to the problem. I have frequently found that in these cases,correction will take longer to achieve, as the debilitating effects of poor saddle fit (especially long-standing issues) can long outlast the change to a new, better-fitting saddle. In bodywork terms, the hypertrophic M. spinalis cervicis is often the last affected muscle to let go.

It’s as if Spinalis cervicis is the emergency worker who will not leave until everyone else is safe.

Bodywork Notes

I am fortunate, in that my modalities enable the gentle release of joints through a non-invasive, neuromuscular approach. The responses I’ve had from horses when M. spinalis cervicis et thoracis has been addressed in isolation have been hugely informative.

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Appendix: Spinalis in the Textbooks

I’m going to add Spinalis references to this post on a regular basis, as I come across them. It’s interesting to see how much, or how little, the muscle is referenced in various textbooks.

This image, from Equine Back Pathology, ed. F Henson 2009, shows acute atrophy of Longissimus dorsi due to neurological damage. It’s still possible to see the raised attachment/origin of Spinalis cervicis et thoracis – the highlighting is mine. Spinalis does not appear in the book’s index. (added 23 Dec 2016)

I have also altered this image, in order to show M. spinalis cervicis more clearly. This is Fig 2.16 from Colour Atlas of Veterinary Anatomy Vol 2, The Horse, R Ashdown and S Done. Spinalis cervicis is within the bounded area and it’s possible to see how it overlies the lamellar part of the nuchal ligament, lamellar portion. (added 23 Dec 2016)

The muscle is tinted green in this image from Sisson and Grossman’s The Anatomy of Domestic Animals, Volume 1, fifth edition 1975. Here, it is labelled Spinalis et semi-spinalis cervicis. This anatomical figure is credited to an earlier text, Ellenberger and Baum, 1908. (added 23 Dec 2016)

James Roony dedicates two pages to the ‘suspension bridge’ theory of the vertebral column in The Lame Horse (1988). His interest is in Spinalis dorsii section of the muscle and its effect behind the withers, in conjunction with Longissimus dorsii. (added 4 Jan 2017)

Master Saddler Jochen Schleese refers to Spinalis dorsi and its function in stabilizing the withers in Suffering in Silence, his passionate book about saddle fitting from 2014. “This muscle area is especially prone to significant development – especially with jumpers – because it is continually contracted to accommodate the shock of landing”. The surface area of the muscle is indicated in the anatomical figure, reproduced here. (added 23 Dec 2016)

In his seminal text addressing issues of modern dressage training, Tug of War, 2007, Gerd Heuschmann includes Spinalis cervicis in the triangle formed by the rear of the rear of the cervical spine, the withers, and the shoulder blades, “… an extensive connection between the head-neck axis and the truck… it explains how the position and length of the horse’s neck directly affects the biomechanics of the back.” (added 31 Dec 2016)

How The Anatomy Books (Unintentionally) Fail Us Over The Nuchal Ligament

July 13, 2014 by Jane @ THB 5 Comments

The nuchal ligament is a soft tissue structure that is widely discussed in dressage circles. Unsurprisingly, given its deep location, relatively few of us get to cast eyes on it or feel it directly under our hands.

It’s equally unsurprising, then, that most of us don’t realize that the image we hold in our heads is somewhat different to the reality of the ligament inside our horse.

© All text copyright of the author, Jane Clothier, www.thehorsesback.com. No reproduction of images, partial or entire text without permission. Sharing the link back to this page is fine. Please contact me for more information. Thank you!

I have recently been fortunate enough to attend another dissection with renowned Australian gross anatomist (and she will point out repeatedly that despite this title, she is not gross – or, at least, not that often), Sharon May-Davis.

In this dissection workshop, Sharon had yet another opportunity to show us that an aspect of textbook anatomy is incorrect.

Yes, apparently there are many points where this is the case.

Where the nuchal ligament is and what it connects

The structure in question is the nuchal ligament, or the nuchal ligament lamellae to be exact.

George Stubbs illustration — George Stubbs, 1777, showed the NLL attaching from C2 to C7.

To quickly explain, the funicular part of the nuchal ligament is the cord-like part that runs from the withers to the occiput (back of skull). The lamellae is the fibrous sheet-like part that extends from the funicular part to the cervical (neck) vertebrae.

According to the majority of anatomy diagrams and textbooks, it extends down to attach to the cervical vertebrae, from C2 to C7.

According to Sharon, it doesn’t. And here’s why.

Findings on the nuchal ligament’s true location

In this study of 35 horses on the dissection table, Sharon found:

No cases where the attachments were from C2 to C7.
No horses where the attachments were from C2 to C6.
In all 35 horses, the attachments were from C2 to C5.
And in 9 of the 35, the attachments to C5 consisted of thin and feeble fibers.
The horses were of a mixture of identifiable breeds, aged 2 to 28 years old.

So, why do the majority of anatomical drawings of the deeper structures of the horse show something different?

When received knowledge can be a problem

Nuchal ligament, 5yo TB [click to enlarge]

Many of today’s illustrators are referring to illustrations that have themselves been amended from earlier illustrations.

(The header image for this site’s most viewed post, The Disturbing Truth About Neck Threadworms and Your Itchy Horse, shows an inaccurate rendering of this ligament, as do most of the other illustrations I used. Dang!)

Inaccuracy is a recognized problem when it comes to received knowledge – was this anomaly due to an earlier artist’s error, or was it a characteristic of some 17th century horses that has been progressively bred out over subsequent centuries?

And this raises the question of which structure, exactly, is supporting the base of the neck of the horse in motion? Read more about m. Spinalis cervicis in this post, Meet Spinalis, the Forgotten Muscle in Saddle Fitting.
And how does this awareness inform current training approaches that require horses to raise themselves into self-carriage?

The findings from this study are in a peer-reviewed paper by Sharon May-Davis and Janeen Kleine currently in press with the Journal of Equine Veterinary Science. The paper includes a detailed review of illustrations in equine anatomy literature, an explanation of the study, and a thought-provoking discussion on the implications for our understanding of equine biomechanics.

Variations and implications of the gross anatomy in the equine nuchal ligament lamellae, Sharon May-Davis, Janeen Kleine, Journal of Equine Veterinary Science 30 June 2014 (Article in Press DOI: 10.1016/j.jevs.2014.06.018)

Have you read about Sharon’s findings on arthritis of the humeroradial (elbow) joint in all ridden or driven horses?

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Buying an Ex-Racehorse: Can You Spot the Major Physical Issues?

February 9, 2014 by Jane @ THB 131 Comments

The ex-racehorse: a huge heart, a strong work ethic, great athleticism, wonderful sensitivity… and, potentially, a host of physical issues. Are you able to identify the problems so often present in these superb equine athletes?

A sports career can be tough on the body, as any committed athlete will admit. No matter how successful the athlete, the wear and tear and dings and dents will just keep on coming. It’s an inevitable consequence of making the body work at its outer limits of strength, speed and endurance: there are going to be times when the body just can’t make it or just can’t take the pressure. And that doesn’t count the spills and collisions that happen along the way. The same is as true for any top athlete as for any trainee who doesn’t make it past the foothills of success. And the same is definitely as true for racehorses as for any human Olympiad.

All text (c) Jane Clothier, https://thehorsesback.com No reproduction without permission. Thanks!

The damage carried by ex-racehorses

Just how much damage an ex-racehorse displays in its physique depends on several things:

the methods of training used,
the speed with which the training was introduced and stepped up,
the athletic qualities of that horse’s body – conformation, maturity and sheer unquantifiable athleticism,
the treatment given and recovery time allowed for injuries at the time they occurred – assuming all were recognized (not all are visible or obvious),
the demands placed on the horse in terms of number of races and recovery time between races,
the length of time spent in racing, enabling the above to occur,
the horse’s mental and emotional ability to cope with physical problems (it varies enormously).

As in any sport, there are things that are done well, and things that are not done so well. Informed training and misinformed. Well judged and misjudged. Just as in the rest of the equine world.

Some thoroughbreds come out of the racing industry in fine fettle and have splendid second athletic careers in high end competition. Many have lower level issues that come right with some rehabilitation, leaving them suited to successful but less demanding careers. Others may be more suited to recreational homes, where life is one long pleasurable trail ride.

Unfortunately, many thoroughbreds with moderate problems land up in homes with people who are quite unaware of their horses’ issues.

What would you look for when buying an ex-racehorse?

When working with clients, I see a range of issues that come up again and again in ex-racehorses. I also see plenty of unsuspecting owners who didn’t know what they were buying at the time.

There’s a huge amount of love around, but the horse is often showing discomfort or pain, and the owner is only just realizing that (a) their horse may not be able to participate in the activities they’d hoped to experience together, and (b) getting the horse to a point when they can deal with these issues may cost considerably more than the horse did upon purchase.

It’s a sad situation. I believe that when looking at ex-racehorses, even those that have already had a couple of non-racing owners, you could do a lot worse than check for the physical issues listed here. Even better, get a vet to check the horse… but even then, you could run through this checklist before getting the vet in.

Don’t forget to read this guest post: 8 Golden Rules for Helping Your Thoroughbred Get Right Off The Track

There’s functional and not-so-functional when it comes to ex-racehorses

Not all the physical issues are deal-breakers, of course. A horse can have one or two and still be able to function perfectly well (although if it’s straight out of racing, some rehabilitative work is going to be necessary). A big part of your buying decision will come down to:

the number of issues you can identify,
the severity of those issues,
what has already been done to assist the horse with those issues,
how much they will affect the kind of riding you wish to do, and
whether YOU are capable of providing the rehabilitation and retraining needed to support the horse through those problems – or if not, whether you can afford to pay somebody else who can.

The list that follows is by no means exhaustive – there are always more problems, especially as a combination of different problems can throw up further secondary issues. And I don’t go into hoofcare, which is worthy of another introductory article in its own right. However, it’s a major issue, so I’d recommend learning more about that too.

What I’ve decided to focus on here are problems that you can identify quickly and relatively easily. Most are visually identifiable. You can then get a more knowledgeable person to help you assess the horse or get a vetting completed before making a decision. Better still, do both.

1. Sacroiliac Damage – Not Whether it’s There, but is it Slight, Bad or Appalling?

This problem really is the number one, as every ex-racehorse has damage to the ligaments in this area. Depending on severity, there can be lesions that have healed, or lesions that have resulted in lasting weakness.

Frequently, when damage to the ligaments is severe, there’ll be further changes to the pelvis that are also visible. These may may or may not have the same root cause (see 2, below). One general rule, though, is that the horse won’t be symmetrical.

Major damage can rule out a future athletic career, while moderate damage may require rehabilitative work to strengthen the back and prepare the horse for future work. Minor damage isn’t necessarily an issue once the ligaments have healed.

Check for: asymmetry of the tuber sacrales (the two bony ‘pins’ of the croup), with one side being more than 5mm higher than the other. The horse may walk with one side of the pelvis lifting higher than the other – a hip ‘hike’. The muscle development over the glutes on top of the hindquarters may be uneven. These horse are nearly always cagey about picking up a back foot – they’ll swiftly lift it really high and then lower it into position. The horse can also find it hard to stand square, instead standing with hind feet close together – one toe may be angled outwards. Always look for problems with the lumbar spine as well (see 3, below).

2. The Pelvis Can Be Equine Ground Zero

As well as sacroiliac problems, ex-racehorses can have other structural damage to the pelvis. Some of it you can see, some of it you can’t. The most important thing to do is check the pelvis for overall symmetry. What you’re checking for isn’t just pelvic rotation, ie. one side being higher or further forward than the other, but also distortion.

In horses that have had heavy accidents at a young age, the pubic symphysis (the lower cartilaginous join between the pelvic halves, directly between the legs) hasn’t formed properly. The pelvis may be forced wider due to impact or stress, and this part never joins.

What problems does this cause? With a severely distorted pelvis, a horse can’t work equally well on both reins and may not be able to canter at all on one rein. These horses also have a higher risk of having hidden stress fractures – hairline fractures that can worsen after a further fall or trauma later in life.

Indeed, make sure that all the pelvic ‘bony landmarks’ – the point of hip, point of buttock, croup – are actually present. Sometimes fractures lead to ‘knocked down hips’ or one tuber sacral may have dropped due to a fracture of the pelvic wing.

Check for: Pelvic symmetry, by checking the positions of the bony landmarks. If you know the horse and it’s safe, stand on a box a few feet behind to take a look down the back of the squared up horse (if it can square up, that is). Otherwise, hold a mobile phone directly overhead to get a straight-down-the-back photo, ensuring it’s dead center. ALWAYS STAY IN A SAFE POSITION – CLIMB ON A FENCE TO LOOK, WHATEVER. JUST STAY SAFE.

© All text copyright of the author, Jane Clothier, www.thehorsesback.com. No reproduction of partial or entire text without permission. Sharing the link back to this page is fine. Please contact contact me for more information. Thank you!

3. Heading North, South, East or West… the Lumbar Spine

If you’ve found any sacroiliac or pelvic issues, you’ll probably find problems in the lumbar spine too. Lateral imbalance in the pelvis will, more often than not, rotate the lumbar spine to one side or the other. Lumbar issues can also be found all on their own.

A long-term rotated lumbar spine will usually have some fusion between the vertebrae, and/or overriding dorsal processes (the part of the vertebrae you can feel). Fused areas are painful for the horse while they’re happening, and OK once the fusion is complete. But if fusion cracks, it can once more be extremely painful. Many horses compete just fine with some fusion, but if it’s severe, there’ll be problems with flexion, both vertical and lateral.

Check for: Use your hand to check the lumbar spine for the ‘lumps and bumps’ that can indicate overriding processes. Looking from the side, is the lumbar spine raised – ie, a roached back? This will usually tilt the pelvis back if it’s a longer term problem. If the pelvis is tilted forward, you’ll find there’s often a longer dip in front of the croup – the sacrolumbar gap is larger than normal.

4. Knee Bones: Take a Bag of Chicklets and Shake Them Up

Or so said Tom Ivers, one of the original equine sports therapy experts and a racing trainer to boot. Equine knees are delicate and complex, with many small bones (carpals), and undergo a lot of stress in a racing career.

Problems such as slab fractures and bone chips in the carpal bones happen due to over-extension (when the joint is bent back slightly) at high speed, or from constant loading on the same bend. Then there are more complex fractures, when the carpal bones break into more than two segments.

Check for: Puffiness around the joint, especially in front, due to previous swelling in the joint capsule. Old bone chips and slab fractures may have been dealt with at the time, but there can be lasting damage within the joint that leads to osteoarthritis (carpitis) later on.

5. The Stresses Left by Sore Shins

An ex-racehorse may have had an episode of sore shins in its early career. This is stress to the periosteum (the soft surface layer over the bone) caused by concussion – the body’s response is to lay down extra calcium to strengthen the bone. The bone recovers, but anywhere there’s been remodeling, there’s weakness in the bone.

If it’s severe, there may be an undiagnosed stress fracture that can go catastrophic under high pressure at a future date.

Check for: a curvature on the front of the cannon, which indicates that the problem was bad for heavy remodeling to occur.

6. Tendons, Tendons and More Damaged Tendons

Injuries to flexor tendons are extremely common amongst racehorses, with the deep digital flexor tendon and superficial digital flexor tendon being the most affected. These can be relatively minor lesions, which heal up quite nicely, to more serious ruptures that end a racing career.

There is always a risk of re-injury due to the weakness, and in serious cases, a second rupture could be catastrophic. It often depends on the quality of treatment and length of rest given at the time, as well as re-conditioning before returning to work.

Check for: a thicker area of the tendons indicates an old injury that has healed, while a curvature along the length of the tendon is a classic ‘bowed tendon’, sign of a far more serious injury.

7. Small but Vital: Fractures in the Fetlocks

Fetlocks are vulnerable due to hyper-extension, when the back of the fetlock comes too close to the ground when all the weight is borne on one foreleg at high speeds. Extremely high forces occur at the back of the fetlock and pastern as the horse lands the forefoot. Poor hoofcare, in the form of ‘low heel, long toe’ imbalance, also plays a significant part in this.

With fractures, the big, big issue is the type and location. A damaged sesamoid (the two small bones at the back of the fetlocks are the sesamoids)can play havoc with the vital suspensory ligament. So if you see signs of a problem, you’ll always need to know more, and that will usually mean involving a vet.

Check for: Sesamoid fractures will show up as ‘over-rounded’ or ‘apple shaped’ fetlocks, where swelling from an old injury has disrupted the joint capsule and/or extra calcium has formed around a restricted joint. Are the fetlocks of the forelegs the same size and shape? If one joint is larger and rounder, or if the ligament at the back of the foot feels thicker, with puffiness above the back of the fetlock, be suspicious.

Original article by Jane Clothier, www.thehorsesback.com posted 9 Feb 2014. All text and photographs (c) Jane Clothier. No reproduction without permission, sorry.

8. The Stifles Cop It, Nearly Every Time

There are numerous causes for stifle issues in ex-racehorses, but you can take the view that if there’s a problem anywhere in the hindquarters, the stifle usually suffers. This includes any pelvic imbalance that leads to unequal loading of the hind limbs, never mind the forces of running on a unilateral bend…

Then there are the rotational twists that can happen in collisions and on bad ground. There are so many ligaments around this complex double joint that it really isn’t hard for it to get compromised.

Check for: A regular click as a hind leg starts to swing forward. This is the patellar momentarily catching, which can happens due to the lateral imbalance (causing misalignment in the femeropatellar joint). Other signs are visual: distension (swelling) of the joint may be visible from the side-on view, or from the front looking back towards the tail, depending on which part of the joint has been affected (femeropatellar or femerotibial).

9. Bringing up the Rear: Hocks Are Vulnerable Too

The hock comes under major stress due to being so involved in providing propulsive power in the gallop. As a major hinge joint, it is central to jumping out of starting gates/barriers, when it’s subject to the load of almost the entire horse. In the gallop, it must alternate between being compressed to absorb concussion, being rigid to build energy, and then extending fully to dispel energy and move the horse forwards.

Frequently, it’s doing this while subject to uneven loading on a bend. Then there are the unplanned twists and traumas. Well-conformed hocks may deal with this pretty well, but over-straight hocks and ‘cow hocks’ mean that the joint is less able to withstand high levels of work. It’s common for DJD to develop in the lower bones of the joint, especially on the side that’s on the inside of the bend the horse raced in.

Check for: look for puffiness on the face of the joint. Also look for bog spavins – these are specific fluid bumps on the front of the joint, which indicate underlying issues. Bone spavins are their bony equivalents, being hard bumps lower on the face of the joint, which indicate the presence of established DJD (arthritis). Also, listen for a crunching noise or a crack when the hind foot is lifted.

10. A Crash and Bang on the Shoulder

Racehorses can experience awkward impacts at the base of the neck, above the point of the shoulder. It can happen when bunched-up horses collide or run against railings, during a fall, or through everyday routine, such as a severe knock against a stable door. One outcome can be damage to the supraspinous nerve, which runs over the face of the shoulder blade (scapula).

When damaged, this can lead to wasting or even paralysis of the muscles over the shoulder blade itself, which is a problem, because these muscles stabilise the shoulder joint. This condition is known as ‘sweeney’. Mild cases usually recover, but more severe cases can be left with permanently wasted muscles. With reduced function in one shoulder and a shortened stride, the horse won’t be suited to demanding sports.

Check for: a lack of muscle over the shoulder blade itself. This is more than just tight muscles – the spine of the shoulder blade will be visually obvious and easy to identify through touch.

And There’s More… There’s Always More

It’s hard to know where to stop with an article like this, but I hope this is a good start when it comes to assessing a horse. You may be thinking that many of the problems are those you should check for in any new horse purchase – and you’d be right. However, anyone who works regularly with ex-racehorses will recognize that there are certain sets of issues that come with these former athletes.

What I haven’t covered: neck issues are common (calcification at the top of the nuchal ligament, misshapen atlas and atlanto-occiptal junction, etc), hidden stress fractures (radius and tibia are most common, but also the scapula… and others), the fractured ribs that come with sideways impacts in a race, misalignment through C6-T4, and quite a few more… but all are harder for the non-professional to assess.

Other information is more of interest to people working in the field. For this reason, I’m adding some links below. Please feel free to mention your own in the Comments…

To finish off, here are two horses that raced in Australia, where it’s common to train horses at the very racetrack where they run most of their races. In the state of NSW, the horses run clockwise (the bay), while in the state of Victoria, they run anti-clockwise (the chestnut). A view straight down the ‘unstraight’ spine can tell you so much!

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Now check out this article OTTB rehabilitation: 8 Golden Rules For Helping Your Thoroughbred Get Right Off The Track

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Revealed: the Common Equine Arthritis You Won’t Read About in Textbooks

November 19, 2013 by Jane @ THB 144 Comments

Sometimes, a person from outside a profession successfully identifies something that has been unnoticed, overlooked or wrongly assessed for a long, long time. Coming from another direction, they see something that has been hidden in plain sight, simply because nobody looked there before.

Update: this post was written with Sharon’s support in 2013. Finally, in 2022, Dr May-Davis is publishing her findings. This article will be updated with full details once her paper is in print in a peer-reviewed journal.

© All text copyright of the author, Jane Clothier, https://thehorsesback.com. No reproduction of partial or entire text without permission. Sharing the link back to this page is fine. Please contact me for more information. Thank you!

One lady who’s working in the field

If you’re looking for a different set of eyes for equine musculoskeletal pathologies, they don’t come much sharper than those of Dr Sharon May-Davis. Few people have the razor sharp eye she has for a hidden pathology or condition in the horse.

Teaching biomechanics, Sept 2013 — *Sharon, seated, teaching biomechanics, Sept 2013*

Sharon is also a biomechanics expert and – significantly – a practical anatomist. She has been conducting private equine autopsies for many years – it’s not for nothing that she’s been labeled The Bone Lady and Equine CSI.

She also uses these 2-3 day dissection workshops to teach equine professionals and horse owners more about how their horses move and the damage their bodies can incur as a result of breeding, illness, injury or work.

Sharon is therefore uniquely placed to provide a source of raw data that is all but unparalleled.

Evidence from the dissection table

Some years ago, Sharon noticed an unusual action in the elbow of horses. She mentioned this to qualified practitioners and was informed that this action was quite normal. Not convinced, she began videoing horses prior to dissection and, within a short period of time, was able to match this action to a change in the elbow.

*Humerus, radius and ulna, showing damage to cartilage*

Not to beat around the bush, it’s an unusual form of degeneration in the horse’s elbow joint that involves all three bones. It’s a form of osteoarthritis that strikes the humeroradial joint and the ulna, causing deep and dramatic gouges into the cartilage, and eventually eroding bone.

When the joint is opened up, blood is frequently found in the synovial fluid (haemarthrosis). The fluid also displays decreased viscosity.

This is more than a little bit odd, as arthritis of the elbow is supposed to be rare in the horse.

Yet Sharon has found it to be present in numerous horses that have been euthanized under veterinary supervision for completely unrelated reasons.

Note: that’s not just some horses, but many.

Do you know where the nuchal ligament attaches on the cervical vertebrae? You think so? Evidence from the dissection table might prove you wrong – read more about Sharon’s findings on the nuchal ligament’s lamellar attachments…

This equine arthritis is visible in the living horse

The vital connection from video to dissection has enabled Sharon to indicate the presence of the elbow osteoarthritis in the horses she had been treating as an equine therapist.

It’s easy to spot, being a noticeable jarring in the elbow as the horse moves downhill – a kind of double action. Significantly, it’s what can be termed a gait anomaly, rather than lameness.

Does it sound – and look – familiar? It’s very likely that you’ve seen it in horses before and wondered what it was. The fact is that it’s so common, many people think it’s a normal action. It’s not. It’s a form of equine arthritis.

Sharon tells us she has seen the elbow problem in all types, breeds, sizes and ages of horses. Some affected horses have been elite dressage and eventing competitors. Interestingly, the problem is only presenting in ridden and driven horses.

If never worked, horses appear to remain forever free of this particular joint change.

Why the fuss – isn’t this just regular arthritis?

No. Arthritis of the horse’s elbow is considered to be rare in equine veterinary medicine.

*How it should look: healthy radius and ulna (unridden horse)*

The key to why it doesn’t often get diagnosed and is considered rare could be the absence of visible lameness. The arthritis identified by Sharon does not cause a distinctive lameness in the horse, although it does bring on a notable gait change, with the double step in the joint’s motion on the downhill.

Riders of such horses often just feel that their horse is a bit ‘off’, feeling a hesitation in the movement, but without being able to define the point of origin.

There are a couple more reasons why it’s not very visible: first, the action of the elbow is highly integrated with the overall shoulder action, and second, the massive triceps muscle has a further stabilizing effect on the joint.

*Radius and ulna of ridden horse, showing cartilage wear and blood in joint*

And even if the elbow is explored, the relatively tight joint space means that degenerative problems are rarely seen in diagnostic imaging, although inflammation can show up in thermographic images.

When, unusually, a problem has been recognized and vets have attempted a corticosteroid injection of the joint (which happens to be the most difficult joint to access), blood has been found to be present.

A closer look at Sharon’s findings

Sharon May-Davis first presented some of her findings into elbow arthritis at a conference in Australia in February 2013: the Bowker Lectures at the Australian College of Equine Podiatherapy. Presenting alongside Prof Robert Bowker and Dr Bruce Nock amongst others, she discussed the club foot in the horse, and noted how the elbow degeneration she observes on the dissection table is always worse in the forelimb with the more upright hoof.

If the condition is bilaterally present, it unfortunately appears worse on the side with the slightly upright or higher hoof. What’s more, and according to Sharon, this also applies to the limb where an inferior check ligament desmotomy (surgery undertaken with the aim of correcting an upright hoof) has taken place and the ligament has later reconnected.

She has, as already mentioned, since established that it can occur in any ridden or driven horse. Here, she describes the problem in her own words.

“The action looks like a slip and or clunk into the shoulder or a shudder or a sliding / slipping action. It depends upon your perspective. The actual change in the action begins when the foreleg is in the ‘Stance Phase’ during the stride as the limb goes into the posterior phase of the stride. It is more obvious going down a hill.

“So far, 100% of ridden horses exhibit this condition to a varying degree (under dissection). Horses not ridden and with no abnormalities do not exhibit this condition (under dissection). Horses in harness also exhibit this condition.

“What does the joint look like? There appears under dissection to be substantial degradation in the cartilage of the humerus, radius and ulna.

“Most horses appear to handle this condition and continue with a normal life if not pushed to extremes. Although this sounds career-ending, in fact it is not. Once the horse gets through the worst of the wear pattern they re-settle in the joint and continue on with work.

“High level competitors require joint support to help sustain the elbow and other joints that may compensate for the change in action.

“Horses that jump are more inclined to land with straighter forelimbs. Be mindful that jumping and downhill work could possibly make the condition worse.

“Riders often feel instability in the horse’s forelimbs when traveling downhill and some even question the horse’s proprioception.

“Bodyworkers massaging the triceps (particularly the lateral triceps) actually exacerbate the condition as the massage releases the cast-like formation that this muscle provides.”

Here are some more examples of the elbow in action.

More research is needed, but so is support

Humerus and radial bones of ex-racehorse, showing arthritic wear — Humerus and radial bones showing arthritic wear

Despite finding and documenting a huge number of dissection cases involving this particular issue, all unaided and unfunded by outside bodies, Sharon has consistently met with brick walls and skeptical responses when she has put the information forward to relevant authorities.

Why? It’s not as if she’s new to this. She has previously identified congenital malformations in the caudal cervical vertebrae of thoroughbreds, and in the atlas of Spanish Mustangs, as well as asymmetries in the femur structures of racehorses due to racing (published in the Australian Veterinary Journal).

She isn’t looking for funding (although she obviously wouldn’t say no), but would like to have this research taken up for the benefit of all ridden and driven horses. The sooner the problem is recognized and investigated, the sooner that episodic pain in the horse can be recognized, with appropriate joint support or rest given where appropriate.

And the sooner we can all learn more in our great drive towards improved equine health, the better. As Sharon says,

“In truth, we are still in the dark. Seeing it is one thing, analyzing it and providing a preventative program is something totally different.”

Questions, thoughts or comments? Join us at The Horse’s Back Facebook group.

More Information

Sharon May-Davis, PhD, M. App. Sc. (Ag and Rural), B. App. Sc. (Equine), ACHM, EBW, EMR was the Equine Therapist for the Modern Pentathlon Horses and the Australian Reining Team at the Sydney 2000 Olympics. She has worked with the Australian Champion from seven differing disciplines and has a particular interest in researching the musculoskeletal system. She also conducts clinics and seminars in relation to her work and regularly presents in the Northern and Southern hemisphere.

Scabbed, Scalded and Sore – Wet Weather and Your Horse’s Skin

February 3, 2013 by Jane @ THB 3 Comments

It’s not much fun being hit by a years’ worth (or more) of rainfall in a few days, as dwellers on Australia’s east coast are yet again experiencing.

In the aftermath of the storms, we often witness a problem common to horses caught in the big summer deluges of the tropics and sub-tropics.

Please note: if your horses has been trapped in deep water, as has happened in some areas of NSW in 2021, your local veterinarian or emergency veterinary services are your first port of call. This post is very much aimed at horse owners in non-emergency situations with non-traumatised horses.

It was originally published after ex-Tropical Cyclone Oswald hammered the South East Queensland and New South Wales coast for several days in January 2013.

The Cause: Mud Fever, aka Greasy Heel

There’s no doubt about it, Aussie owners aren’t as familiar with mud fever as owners in countries that are far more – well – muddier. Hailing from England, I know about it only too well. Yet in this wide brown dry land, where it also goes under its local name of greasy heel, it’s far less common.

Or at least, it was less common. I’m seeing a lot more in ~~2021~~ 2025 than I did in 2013.

The cause of the swelling and crusting skin we see with mud fever is a reaction to the early stages of bacterial or fungal infection.

Put simply, during the periods of unrelenting rain, the skin becomes softened and the many microscopic scratches around the pasterns and lower legs are exposed (imagine tiny scabs going soft).

The ‘bugs’, which thrive in damp conditions, enter these tiny scratches and abrasions. As the horse’s body starts to fight the invaders off, the swelling occurs.

Not all horses will develop the problem further, as it depends on how strong their immune systems are. Some will fight it off. But while there’s visible swelling, possibly accompanied by redness on white legs, sometimes with crusting skin and the beginnings of scabs, the horse’s body is in defense mode.

The problem usually affects the hind legs more than the front, but as it progresses, all four legs can be affected.

Partner in Crime: Rain Scald

Rainscald, also known as rain rot, is caused by the same bacterial agents and is also a form of dermatitis. The bacteria cluster in the damp, warm zone at the base of the hair, next to the skin.

You don’t see the signs as quickly as with greasy heel, but you may notice your horse has increased sensitivity along the centre line of the back – especially if they are rather overweight and have a ‘rain channel’ down the middle.

Where Does Greasy Heel Come From?

Both rainscald and greasy heel/mud fever are caused by an invading dermatophilus or staphylococcus. Greasy heel may also be caused by fungal infections such as dermatophytes.

The microbes that cause rainscald are often already living on the skin of horses, without causing any problems. However, during a period of heavy rainfall, especially in our warm regional climate, they become more active and release ‘zoospores’.

They get happy: they breed.

The spores infect the skin where it’s weaker, with the discharge then clogging into the familiar paintbrush tufts of hair and scabs after a few days.

It’s entirely possible that some paddocks present horses with the greasy heel and rainscald bugs more than others. I’ve certainly had horses that were fine until they changed properties and then suddenly seemed to ‘pick something up’.

Why Is This Such a Problem After Storms?

Good question. It’s not as if we don’t regularly get 2 or 3-day episodes of non-stop rain. The high incidence of swollen legs relating to mud fever may be due to several things. Shall we speculate?

Was the weather extremely hot before and after, and maybe during the event? The conditions may have been particularly favorable to the bacterial activity.

If there’s rain and also high winds, it’s likely that horses stopped moving around as much.

Lack of movement leads to poor circulation, which leads to fluid build-up anyway, as well as reduced resistance to nasty little pathogens.

But in truth, I don’t know for sure. I’d be interested to hear other ideas. (There’s a comments section at the end.)

Whatever the reasons, I still feel it’s best to come down hard on problems like mud fever or rainscald, as they’ll only come back another time, making your horse uncomfortable and setting you to work on it all over again.

Are These Skin Problems Serious?

These infections can be surprisingly painful for the horse. If your horse has greasy heel and scabs form, and your property is still flooded or at the least muddy, then you need to act quickly if it’s not to become a more serious problem.

The horse needs to flex at the fetlocks whenever it moves, so if the scabs remain on the pasterns, they will crack repeatedly and the lesions beneath will grow larger.

(This is why the condition is also known as cracked heel.) Your horse may well become lame.

Rainscald is painful for the horse even before the ‘paintbrush tufts’ appear. It will remain so until the scabs have all come away and the skin beneath has healed.

Horses severely affected by rainscald may develop a fever, become depressed, lose their appetite and become lethargic.

They may also have swollen lymph nodes… these are all signs of a body defending itself against pathogens.

How to Treat the Bacteria

Once you realize you’re looking at infection, it becomes more apparent that something needs to be done. There are many suggested remedies you can try once the reaction has started – here are a few.

The initial swelling should subside with movement and exercise, as the lymph fluid is shifted away.

If the horse has developed scabs, you can soften and remove these before applying treatments.

I’ve previously used aqueous cream for small scabs, which soaks and lubricates them, so that they then slide off gently. I’ve also seen paraffin oil or olive oil suggested. If the scabs are covering much larger lesions, you may need to progress more slowly, over several days, as removal will be painful for the horse.

Here are some treatments you can try, recommended by different people in the equine industry.

A diluted iodine solution can be used on the legs, to zap the bacteria.
For greasy heel and rainscald, an anti-microbial shampoo is another option for scab removal – Maloseb, normally used for cats and dogs, is gentle and contains chlorhexidine gluconate (2% content).
For rainscald, you can ease off the scabbing at an early stage, either with an oil-based product, or even with olive oil, before rinsing the back with iodine. Use it well-diluted or it may sting.
Products used by vets and medical staff containing chlorhexidine gluconate offer a gentle antibacterial action. Microshield is a good product (5% content) that can be diluted and used on horses’ legs and backs. You can buy it online or from Chemists Warehouse in Australia.
A poulticing product such as Tuffrock can be applied to the affected areas. This has some antibacterial properties – if scabbing is present, it’s better to also use an antibacterial agent.
The herbal approach is to use coconut oil on the lower legs. You could also try using this before the rains come, providing you have advance warning, so that a protective layer is built up. This can help prevent bacteria from entering the skin.

Make Greasy Heel Go for Good

If infection is present, you may need to work on the area for a few days running to ensure that the bacteria are well and truly zapped. You want to reduce the chances of it recurring – ridding your horse’s skin of the bacteria is definitely one way to do that.

That’s not to say it’ll never happen again, but as ever, prevention is better than cure.

One of the most helpful things we can do for our horses is to work on their underlying condition, boosting their immunity through use of probiotics to improve gut function, while providing adequate nutrition and mineral supplementation.

And – well, I would say this – bodywork will ensure the upper layers of tissue, including the skin, are nourished and functioning as they should, while circulation is good.

Extreme weather is never easy to deal with, but with a bit of organization, we can ensure our horses come safely through it without experiencing an unnecessary degree of discomfort and even pain.