Inside the Horse – An Equine Anatomy Exhibition. August 2026

  

Discover how your horse really works at "Inside the Horse", an immersive equine anatomy exhibition from Horses
Inside Out. 

 

Designed for everyone from curious horse owners to experienced professionals, this exhibition offers the chance to explore one of the UK's most extensive equine anatomy collections.

 

See real skeletons, anatomical specimens and interactive displays, while learning about bones, joints and biomechanics, muscles, tendons, ligaments and fascia, the digestive system and gut health, common injuries and diseases, and teeth, ageing, growth and development.

 

Public open days: 14–16 August and 21–23 August 2026

 

Whether you're passionate about horse welfare, performance or simply want to understand horses better, this exhibition offers an insight into the horse from the inside out.

 

For a 10% DISCOUNT use the code AX10

 

To book, and for more details, go to:

 

https://www.horsesinsideout.com/inside-the-horse

Ageing, blood supply and tendon health: new research

Photo: RVC

 Tendon injuries are one of the most common causes of lameness and loss of performance in
horses, particularly as they get older. 

A new study from the Royal Veterinary College (RVC) has shed important light on why ageing tendons are more vulnerable to injury and slower to heal, by closely examining how the tendon’s blood supply changes with age.

 

Tendons are specialised tissues that transmit force from muscle to bone. To do this efficiently, they are dense and tightly packed with collagen fibres. While this structure is excellent for strength and elasticity, it comes at a cost: tendons have relatively few cells and a limited blood supply compared with other tissues.

 

Blood vessels are vital for delivering oxygen and nutrients, removing waste products and supporting repair after microscopic damage caused by normal exercise. Because tendons are already poorly supplied with blood, any further reduction can seriously limit their ability to maintain healthy tissue and to heal after injury.

 

The study focused on the superficial digital flexor tendon (SDFT) in horses. This tendon is frequently injured in athletic horses and is considered the functional equivalent of the human Achilles tendon. This makes the horse an excellent model for understanding tendon ageing in both veterinary and human medicine.

 

The research team, led by Dr Nodoka Iwasaki, Postdoctoral Researcher, and Dr Chavaunne Thorpe, Lecturer in Basic Sciences at the RVC’s Department of Comparative Biomedical Sciences, used advanced 3D technologies (micro-computed tomography (μCT) and confocal microscopy) to capture detailed images of tendon tissue from young (2-5 years old) and older (18-22 years old) horses, enabling them to visualise and quantify the tendon’s vascular network in unprecedented detail. 

 

This approach allowed the researchers to map the tendon’s microvasculature in unprecedented detail.

 

The μCT analysis showed striking age-related changes in the tendon’s blood vessels, particularly within the interfascicular matrix (IFM)  (the region between tendon fibre bundles that is important for tendon elasticity and repair.)

 

In older horses, compared with younger ones, there was:

·      70% reduction in total vascular volume

·      30% reduction in average vessel diameter

·      74% reduction in vessel density

 

In simple terms, older tendons had far fewer and smaller large blood vessels. This leads to significantly reduced blood flow, helping to explain why older tendons are more prone to degeneration and slower to heal.

 

At the same time, the immunolabelling studies revealed something unexpected. Markers associated with endothelial cells (cells lining blood vessels, identified using von Willebrand factor, VWF) and pericytes (support cells that stabilise small blood vessels ) were increased in aged tendons. 

 

This suggests that new, very small blood vessels (capillaries) are forming. However, these new vessels appeared disorganised and were not accompanied by healthy larger vessels. The researchers also found major reductions in markers associated with mature, functional vessel walls (such as MYH11 and desmin), indicating a loss of normal vascular structure.

 

Taken together, the results suggest that ageing tendons lose their well-organised, larger blood vessels and attempt to compensate by forming many small, immature vessels.

 

This disorganised angiogenesis may be driven by low-level inflammation or repeated micro-damage over the horse’s lifetime, but further research is needed to confirm this.

 

Crucially, these new small vessels may not function effectively, meaning they do not adequately restore blood flow or support proper healing.

 

This research helps explain several real-world observations:

·      Older horses are at higher risk of tendon injury

·      Tendon injuries in older horses heal more slowly

·      Re-injury rates are high due to poor-quality repair and scar tissue formation

 

Understanding these vascular changes may help:

·      Identify horses at higher risk of injury

·      Tailor training and workload more carefully as horses age

·      Improve rehabilitation strategies by recognising the limits of tendon healing in older animals

 

By identifying specific age-related changes in tendon blood vessels, this study opens the door to new therapeutic approaches. Potential future strategies may aim to:

·      Preserve healthy blood vessels as horses age

·      Improve vascular organisation during tendon healing

·      Enhance regeneration rather than scar formation

 

Such advances could significantly improve outcomes for older horses with tendon injuries and may also translate to better treatments for tendon injuries in people.

 

In summary, this study provides the first detailed 3D picture of how tendon blood supply changes with age. It shows that while older tendons try to adapt, the loss of healthy, functional blood vessels is likely a key reason why ageing tendons are more fragile and slower to heal.

 

For more details, see: 

 

Nodoka Iwasaki, Jack Llewellyn, Jeanne Brown, Danae E. Zamboulis, Elizabeth J. T. Finding, Caroline P. D. Wheeler-Jones, Chavaunne T. Thorpe

Immunolabelling and Micro-Computed Tomography Revealed Age-Related Alterations in 3D Microvasculature of Tendons.

 Aging Cell (2025) e70293.

https://doi.org/10.1111/acel.70293

Horses Inside Out Conference 2026

 Gillian Higgins has announced the 2026 Horses Inside Out Conference, with early bird tickets now available.

The conference will focus on Soundness and Symmetry in the Horse - the balance and harmony of the musculoskeletal system and its impact on movement. Across the programme, speakers will explore what soundness and symmetry mean in practice, how training and management can support them, and the challenges that may arise along the way.

Designed for professionals and equestrians from all disciplines, the event offers a rare opportunity to hear from world-leading experts, share the latest research, and consider practical applications to improve the health, welfare, training, and performance of horses.

The 2026 conference will differ from previous years with a three-day structure: two days of presentations followed by a practical day. The first two days, held at Holywell Park Conference Centre, Loughborough University (UK), will feature lectures from leading equine professionals on anatomy, biomechanics, training, and therapy. The third day, will focus on Soundness and Symmetry in Practice, with live demonstrations and practical sessions led by guest experts.

For more details, see: 

https://www.hioconference.com

Correlation between mild changes on back radiographs and performance

(c) Sergii Kumer Dreamstime.com

 Mild radiographic abnormalities of the thoracolumbar spinous processes do not necessarily impair performance in warmblood jumping horses.

Back pain is a well-recognised contributor to reduced performance in sport horses. However, the precise relationship between clinical signs of back discomfort and radiographic abnormalities of the spine remains poorly defined.

A recent descriptive observational study, published in the Journal of Equine Veterinary Science, aimed to characterise radiographic findings of the thoracolumbar spinous processes in actively competing Warmblood show jumpers and to assess any associations with performance outcomes.

The study evaluated 100 Warmblood jumping horses, all competing in 2018, with a median fence height of 1.35 m (mean 1.3 m; range 0.90–1.60 m). All horses included were free from observable lameness and neurological deficits. Lateral radiographs of the thoracolumbar spine were obtained and assessed by four independent observers, who graded each image for the presence and severity (absent, mild, moderate-to-severe) of four specific abnormalities: narrowed interspinous spaces, sclerosis, lucency, and enthesopathy.

Inter-observer agreement was assessed using the Intraclass Correlation Coefficient (ICC), revealing moderate to good consistency across observers.

In addition to radiographic evaluation, signalment, years of competition, current level of performance, and highest career performance level were recorded for each horse. These variables were then analysed for correlation with radiographic findings.

Strikingly, no horse in the study population was entirely free from radiographic abnormalities, highlighting the high prevalence of such changes among active sport horses. Narrowed interspinous spaces and sclerosis were the most commonly observed findings, predominantly located between thoracic vertebrae T15 and lumbar vertebra L1. Enthesopathy was most frequently identified at the withers, specifically between T8 and T13.

Despite the high prevalence of abnormalities, the research team found no significant correlations between radiographic changes and the horse's age, current performance level, or total years of competition (p > 0.05). Interestingly, the highest career performance level showed a weak but statistically significant positive correlation with the presence of narrowed interspinous spaces and sclerosis. These findings suggest that some radiographic abnormalities may not only be tolerated by high-performing horses but could also reflect adaptive or age-related changes without clinical relevance.

In conclusion, mild radiographic changes of the thoracolumbar spinous processes—particularly narrowing of interspinous spaces and sclerosis—were commonly observed in this cohort of active Warmblood jumpers. Importantly, these findings were not associated with impaired performance, indicating that such abnormalities, when mild and absent of clinical signs, may not adversely impact athletic function.

 

For more details, see:

 

M.P. Kerbert, S.S. le Jeune, K.L. Philips, K.L. Shaw, C.A. Erickson, P. Espinosa-Mur,

Mild radiographic abnormalities of thoracolumbar spinous processes are not associated with decreased performance in 100 Warmblood jumping horses in active competition,

Journal of Equine Veterinary Science,(2025)

Vol 147, 105366,           

https://doi.org/10.1016/j.jevs.2025.105366

Ultrasound appearance of patellar ligaments

(c) Sergeii Kumer Dreamstime.com

 A new report highlights that ultrasonography should not be solely relied upon to diagnose patellar ligament damage as a cause of lameness in horses.

Ultrasonography is a valuable tool for evaluating soft tissue injuries, but accurate interpretation requires an understanding of normal tissue appearance. Changes in tissue structure may be mistaken for disease when they are, in fact, normal variations.

Since tendons and ligaments do not appear well on X-rays, ultrasound is a preferred method for diagnosing soft tissue injuries in horses’ legs. Ultrasonography works by using high-frequency sound waves, which are emitted from a handheld transducer. These waves bounce off different tissues, such as tendons and ligaments, and return to the device to generate a live image on the screen.

When fluid accumulates between tissue fibres, it can disrupt the normal tissue structure. Because fluid does not reflect ultrasound waves, it appears dark on the screen, while tissue fibres, which reflect sound waves, appear as white spots or lines. Fatty tissue has a different ultrasound appearance compared to fibrous tendon and ligament tissue.

Ultrasonography is increasingly used to investigate potential patellar ligament damage in horses. However, researchers question how much variation in ligament appearance is normal.

A team from the Swedish University of Agricultural Sciences in Uppsala, led by Ellen Law and colleagues from the Diagnostic Imaging Clinic and the Department of Animal Biosciences, conducted a study to examine the ultrasonographic appearance of patellar ligaments (PLs) and the patellar fat pad in healthy horses.

The prospective observational study included 116 horses in training—Cavalry horses, Warmbloods, and Standardbred Trotters. To be eligible, the horses had to be in training with no reported lameness or performance issues according to their riders or trainers.

Researchers used B-mode and colour Doppler ultrasound to examine the PLs and infrapatellar fat pad in both hind limbs. They also conducted objective gait analyses on all 116 horses.

Findings showed that hypoechoic (darker) regions in the intermediate patellar ligament were common (24/116), particularly in the caudal aspect of the mid-third of the ligament. The infrapatellar fat pad typically had a hypoechoic striated appearance, except in one horse, where it was hyperechoic.

There was no association between ultrasonographic findings in the PLs and infrapatellar fat pad and lameness. 

The researchers emphasised that patellar ligament appearance varies among horses, and these variations may or may not be linked to pain. They stressed the importance of using local analgesia to accurately determine the source of lameness before making a diagnosis.

 

 

For more details, see: 

 

Ellen Law , Linda Wright , Margareta Uhlhorn , Elin Hernlund , Carolina Nilemo , Marie Rhodin 

Hypoechoic ultrasonographic findings in the patellar ligaments are common in riding and trotting horses in training (116 cases)

Vet Radiol Ultrasound (2025) 66(1):e13446

 https://doi.org/10.1111/vru.13446

Anatomy workshop

(c) Lifeontheside Dreamtime.com

If you’d like to expand your knowledge of horse anatomy, you might be interested in a three-day dissection workshop hosted by Gillian Higgins of Horses Inside Out at Equine Science Labs, Hartpury University, (Gloucester UK) on April 9th, 10th, and 11th, 2025.

You can choose to attend all three days for a comprehensive whole-horse dissection or select specific days based on your interests. Each day focuses on a different area: Spine, Head & Neck, and Limbs. This hands-on workshop offers a unique opportunity to learn in a professional, clinical lab environment.

Full details are available at:

https://www.horsesinsideout.com/dissection-workshop

Investigating horse hair whorls

Is it possible to gain insights into a horse's character merely by examining its facial features? 

Hair whorls, also referred to as cowlicks or trichoglyphs, are described as variations in hair patterns, and can manifest as circular or linear forms. They are commonly observed on the horse's face, neck, and body.

 

Whorls are hereditary traits in horses and may be linked to temperament and coat colour. 

 

The number and placement of hair whorls have been the subject of numerous superstitions. For instance, whorls on the neck and pectoral region are often considered lucky, while those on the lower part of the thigh, jaw, back, and shoulders are looked upon less favourably.

 

Although the idea that whorl position is linked to temperament might initially seem far-fetched, it becomes less implausible when considering that these features are attributed to the same layer of cells in the embryo as the nervous system, suggesting a connection to early foetal brain development.

 

Some people associate specific whorl patterns with calm and trainable temperaments, and other patterns with more spirited or challenging behaviour. 

 

Ana Encina and colleagues conducted research on whorls in the Pura Raza Española (PRE) horse, the chief native Spanish equine breed. Their study looked at the frequency and genetic parameters, including heritability and genetic correlations, of circular and linear hair whorls on the head, body, neck, and limbs of PRE horses. Factors such as gender, level of inbreeding, birth period, and coat colour were also considered in their investigation.

 

They found that circular hair whorls were more prevalent than linear ones. Linear whorls were less common, with over 90% of horses lacking them on their head and limbs, although more than half display them on their body and neck. Conversely, a majority of horses, especially those with a grey coat, had circular hair whorls below the central line of the eyes. 

 

They conclude that, considering previous correlations between hair whorl position and temperament in cattle, the findings could support a potential link between hair whorl position and a more docile, calm temperament in horses, particularly within the PRE breed and the specific grey coat colour. However, additional research is necessary to substantiate this hypothesis.

 

 

 

For more details, see:

 

Phenotypic and Genetic Study of the Presence of Hair Whorls in Pura Raza Español Horses. 

Encina A, Ligero M, Sánchez-Guerrero MJ, Rodríguez-Sainz de los Terreros A, Bartolomé E, Valera M. 

Animals. 2023; 13(18):2943. 

https://doi.org/10.3390/ani13182943

Online Seminars from Horses Inside Out

Horses Inside Out have announced a series of online seminars to be held later this year. With
three expert speakers, these seminars are aimed at equine professionals and promise to enhance your knowledge in equine health, welfare, genetics, and performance.

 

Understanding Orthopaedic Problems with Dr Jessica Kidd : Saturday, 7 October 2023 

Dr Jessica Kidd will share her extensive knowledge of orthopaedic issues in horses, including caudal neck pain, neuropathic pain, and Wobbler's Syndrome. She will also address regenerative medicine, dispelling myths about joint injections and stem cell therapy. The seminar will cover common problem areas in horses such as the back, kissing spines, supraspinous ligament desmopathy, facet joint arthritis, and the sacroiliac region.

https://www.horsesinsideout.com/understanding-orthopaedic-problems

 

Nature Versus Nurture - Genetic Insights with Dr Andrew Hemmings : Saturday, 4 November 2023. 

Discover the fascinating world of equine genetics with Dr Andrew Hemmings. The seminar will explore evolutionary perspectives on anatomy, management, and behaviour in horses. You will learn about the inheritance of simple traits, such as coat colour, and delve into more complex traits like racing performance and abnormal behaviours, all while examining the interaction between genes and the environment.

https://www.horsesinsideout.com/nature-nurture

 

Equine Comfort and Performance with Dr Chris Pearce & Gillian Higgins : Saturday, 2 December 2023. 

This one-day seminar will focus on the integral role of dentistry, bridle fit, and understanding anatomy in equine comfort and performance. Dr Chris Pearce and Gillian Higgins will discuss the complex anatomical and biomechanical connections of the horse's head and how it can impact the rest of the body and performance. Dental disease, bit, and bridle fit can affect performance, and recognizing signs of discomfort is crucial.

https://www.horsesinsideout.com/getahead

Thoracic asymmetry in ridden horses

 Muscle asymmetry in the thoracic region has implications for saddle fitting. If the muscle on one side of the withers is more developed than the other, this will affect saddle fit, potentially causing pain and discomfort. 

A study, led by assistant professor Dr. Katrina Merkies, at the University of Guelph, Ontario, Canada looked at muscular symmetry at the withers. 

 

Undergraduate students in the Department of Animal Biosciences, Julia Alebrand, Bethany Harwood,  Katharine Labarge and Laura Scott conducted a retrospective study of  490 horses. They studied withers measurements, taken with a flexible withers tracing tool, that had been recorded by a saddle fitting company.

 

Horses of various breeds (from Arabs and Thoroughbreds to stocky Warmbloods and Drafts) and a range of disciplines (dressage, hunter/jumper, recreational pursuits) were included in the study.

 

They found that almost 60% of horses had more muscle on the left side. 

 

In this population of horses, wither measurements were not significantly affected by horse breed, age, sex, height or level of training. Rider age, gender, height, weight and level of training did not affect wither measurements either.

 

The work is reported in Comparative Exercise Physiology. The authors report that horses in their study were asymmetric in their thoracic structure with most being larger on their left side than the right. They suggest that this asymmetry may be due to genetics, environment, or training. Importantly, it should be considered when fitting a saddle to the horse.

 

For more details see:

 

Investigation into thoracic asymmetry in ridden horses

K. Merkies; J. Alebrand; B. Harwood; K. LaBarge; L. Scott.

Comparative Exercise Physiology (2020), Vol 16, 1, pp. 55-62(8)

https://doi.org/10.3920/CEP190025

 

To find out more about the study, watch a video interview with Dr. Merkies

https://www.youtube.com/watch?v=77bUmR0JUZU&t=3s

Looking inside the horse’s gut

 A wireless endoscopy capsule can be used to inspect the inside of the horse’s gastro-intestinal tract.

The “ALICAM system” capsule is 11mm in diameter and 33mm long. It contains 4 micro-cameras, mounted at 90° to provide a 360°panoramic view. The cameras are activated by movement  (this helps prolong the battery life and so increase the length of the digestive tract that can be imaged.) When activated, the cameras record images at the rate of 20 /second and store them on the capsule’s internal memory chip.

Images are only available for inspection once the capsule has passed through the digestive tract and has been retrieved from the manure (using radiography).

Researchers at the University of Calgary have been studying the technique.

Five adult horses with no signs or history of gastro-intestinal disease were included in the study. The researchers assessed different protocols for preparing the horses and found that the one giving most useful images was to starve the horse for 24 hours before introducing the capsule.

Satisfactory images were obtained of the pylorus, major duodenal papilla, individual villi, and ileocecal junction. Visualization of large intestinal mucosa was poor.

Among the abnormalities identified on the images were mucosal erosion, ulceration and haemorrhage, areas of thickened mucosa, and evidence of parasitism.

On average, it took 6.5 days from introduction for the capsule to be retrieved in the manure.

The researchers conclude: “this novel endoscopic capsule appears safe, practical, and non-invasive in horses; however, variability in capsule excretion time must be taken into account for clinical application.”

For more details, see:

A wireless endoscopy capsule suitable for imaging of the equine stomach and small intestine

Mei Steinmann, Rebecca J. Bezugley, Stephanie L. Bond, Jill S. Pomrantz, and Renaud Léguillette

J Vet Intern Med. (2020) 34(4): 1622–1630.

doi: 10.1111/jvim.15825

Evaluating English saddle fitting

Poorly fitted saddles can adversely affect welfare and impair performance of ridden horses. The Saddle Research Trust Research Workshop, held in December 2018, identified a need for improved education of saddle fit evaluation among professional equine practitioners.

An educational article was subsequently commissioned by the editor of the peer-reviewed scientific journal, Equine Veterinary Education, that would simplify the complex subject of saddle fitting evaluation.

The article aims to provide practical guidance to equine veterinarians to assist in their decision-making process whilst carrying out routine assessments when a horse is evaluated ridden, such as for pre-purchase, lameness or poor performance examinations. It also clarifies when a saddle may be contributing to pain and performance problems and when the veterinarian should refer the client to a saddle-fitting professional.

“Evaluating the suitability of an English saddle for a horse and rider combination”, a collaboration between Anne Bondi, Sue Dyson, Sue Norton and Lawrence Pearman, is a comprehensive mini manual aimed at vets and physiotherapists and which will be equally of interest to other professional equine practitioners.

Thanks to the generosity of the publishers, the article is free to view. Go to:

https://doi.org/10.1111/eve.13158