There is an emerging science investigating the link between hoof balance and pathologies above the digit, and in particular, the hind hoof and limb posture. Links between poor hind hoof balance, pathologies in the hind limb and associated altered posture have been suggested but not quantified, and this indicates that postural assessment should become part of farriery protocol and be incorporated into intervention decisions.
The canted-in posture; an abnormal compensatory posture, where the limbs are non-vertical metacarpal/tarsal alignment, is often demonstrated and documented in horses with a lack of alignment of the phalanges and resulting low palmar and plantar P3 angles. Where this is present, there is always unhealthy or pathological hoof morphology, more commonly described as long toe, low heel. There are strong associations established between long toe, low heel hoof morphology and lameness, degenerative disease, injury, and pathology in the digit. More recently, studies indicate a link with negative plantar angles and hind limb pathologies, namely proximal suspensory desmopathy, hock and stifle pathology and lameness. Negative plantar angle (NPLA) is an extreme presentation of long toe/low heels and is associated with progressive collapse of the heels. While not established, it has been suggested that canted-in posture and NPLA can be mitigated by appropriate trimming, trim or shoe cycles and mechanical shoeing.
An ideal palmar or plantar P3 angle has not been established, but healthy hoof ideals depicting healthy hoof morphology are accepted and straight hoof-pastern axis is strongly associated with phalangeal alignment and healthy palmar and plantar angles. Balance or podiatry radiographs can help ascertain phalangeal alignment beyond external observation as this can be somewhat tricky when a horse demonstrates unhealthy limb posture.
Ideally, farriery intervention to address low or NPLA is to improve the pastern to dorsal wall angle by providing elevation while maintaining frog contact and maintaining frog support. This can be done barefoot via a trim with or without an intervention such as a boot and pad, which can be wedged or with shoes and this well depend on the degree of NPLA, posture, soundness and existing pathologies. Shoes should fit to 50:50 proportions around the centre of rotation (COR) of the coffin joint, with 3D wedged pads and dental impression material and these are widely available and commonly used to help support the caudal hoof where open heeled shoes are used.
For more information on this topic, please see Sharp, Y. and Tabor, G. (2022) ‘An Investigation into the Effects of Changing Dorso-Plantar Hoof Balance on Equine Hind Limb Posture’ (https://www.mdpi.com/2076-2615/12/23/3275) and Clements, P.E.; Handel, I.; McKane, S.A.; Coomer, R.P. ‘An investigation into the association between plantar distal phalanx angle and hindlimb lameness in a UK population of horses’ (https://beva.onlinelibrary.wiley.com/doi/abs/10.1111/eve.13186). Many additional resources and links to published papers can also be found also at https://www.theequinedocumentalist.com/blog-1
What is healthy’ ‘ideal’ hoof and posture?
According to modern podiatry and farriery, the following are considered healthy, which we currently agree with and can help you identify a healthy hoof (although the ideal hoof shape or morphology will change somewhat according to the individual horse and even the individual hoof):
Straight (within 3 degrees if observing externally and not from a high quality, properly captured radiograph) hoof pastern axis (or HPA)
Healthy phalangeal alignment and appropriate palmar or plantar P3 angle (as assessed on quality radiographs. This would present as a straight HPA when viewed externally
Appropriate vertical depth, dorsal-palmar and medial-lateral balance – this is also assessed by radiographs and present in healthy phalangeal alignment and morphology
Minimum of 60:40 toe to heel ratio around the centre of rotation of the coffin joint for the barefoot horse, and closer to 50:50 in the shod horse
Maximum of 5 degrees difference between the dorsal wall hoof angle and heel angle
Healthy posture and gait with cannon bones perpendicular to the ground (on a level, firm surface) and ability to stand and remain square when invited
A hoof free from pathology/pathological morphology, in other words, free from disease, infection, flares, cracks or other signs of distortion and unhealthy growth
A hoof score appropriate to the use of the horse, age and health.
You might note we haven’t outlined an ideal palmar or plantar P3 angle (the angle the bottom of the pedal bone sites in relation to the ground surface). We don’t believe there is an ideal angle per se, as this will be determined by the healthy HPA and when there is healthy phalangeal alignment which is subjective and as individual as horses. We vehemently believe the pedal bone should not sit at 0 degrees or even between 0 and 5 and have yet to see evidence that this correlates to a horse with ideal development, posture or healthy hoof morphology.
Finch – hoof score 5/10 and near ‘ideal’ hooves and posture considered healthy for his well-being, soundness and comfort
In this example, we feature an 11hh 12 year old Dartmoor Hill pony called Finch. He has a history of acute and chronic laminitis and is now 100% sound, living out on a grass track 24/7 in a stable herd of 4 ponies. You may recall Finch in this video where our hoof care approach helped resolve his ‘mystery’ lameness in a very short space of time: https://youtu.be/YLk3UzAeUxw
In the picture above, you can see he stands comfortably ‘square’ with both front and hind cannon bones perpendicular to the level ground surface. From this stance, we can take a photo of the hoof from the ground surface, directing the camera at the approximate centre of rotation of the coffin joint (the green circle in the next image) for objective hoof assessment. His withers are higher than his croup and his pastern and shoulder joint are at similar angles. His thoracic sling development could be improved, which would positively impact his hind quarter development and ideal centre of mass, however it could be argued that for a pony not being exercised to improve his development, this stance is reasonably healthy and certainly adequate for his well-being.
In the photo above, one could discern that:
His dorsal hoof wall angle is 62 degrees (number in red at the tip of his toe)
His pastern angle is 65 (red number in the centre of his pastern)
His heel angle is 62 degrees (red number at the base of the heel)
His coronet angle is 15 degrees (red numbers at the coronet band)
His toe:heel ratio is 60:40
His cannon bone is 90 degrees to the ground
There is no evidence of pathology, however there are very minor growth rings in the top third of his hoof
He presented sound, was able to stabilize and balance very well on 3 limbs to be trimmed and showed no signs of physical or emotional discomfort or distress on the day
From this we consider these within healthy ‘ideals’ previously outlined and can confidently provide Finch with a hoof score of 5/10, which as a guide, we consider sufficient for general low intensity, compassionate ridden work 100% barefoot on all surfaces, where a horse or pony properly developed for and accustomed to this role.
Nerve Compression
In addition to well established podiatry and farriery science, there is an emerging science around posture, pathology, behaviour, pain and the manifestation of nerve compression.
One study used 14 young to middle-aged sport horses that became difficult to train and ride after their purchase. Though easy to handle for general care, when asked to work under saddle, they became dangerous. The researchers concluded that the behaviour was caused by nervous system lesions which caused neuropathic pain (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8702524/?fbclid=IwAR0ygzx-PEGfgmLX04-MHUVBi88aQYGIND8jaUu1-MjamcFl-IrfdrvPRi8)
The canted in posture typical with common pathological hoof morphology seen in the UK (long toe/low heel) leads to changes in bio-tensegrity, overdevelopment and underdevelopment of muscles in the horse and this arguably leads to nerve compression, pain and further compensatory posture, stance, gait and negatively impacting on hoof growth and morphology. A vicious cycle can then commence which requires a holistic approach to support development of both the hoof and the body. Integrative equine podiatry combined with nerve compression and BTMM (Balance Through Movement Method) for development and training offers an ideal approach to supporting healthy hoof and body ideals and promoting overall well-being and resilience needed for lasting soundness and longevity in horses.
See https://equineeducationhub.thinkific.com/courses/nerve-impingement-hoof-balance for learning resources on the link between hoof balance and nerve compression. See also https://www.balancethroughmovementmethod.com/academy and https://btmmacademy.com/spaces/11109662/page for free and paid for resources on BTMM and introduction to nerve release, to kick start your horses rehabilitation at home.
Nerve compression is believed to caused by repetitive motions that effect an area where a nerve travels. The lower cervical spine, cervicothoracic region and lumbosacral region are the highest documented regions for compressive neuropathy to occur due to the bundles of nerves which reside there.
Nerve compression is associated with pathological posture, pathological hoof morphology, and changes in behaviour. The causes, symptoms and diseases associated with nerve compression can therefore be varied, sometime multifactoral and make diagnosis difficult.
In one study which used 14 young to middle-aged sport horses that became difficult to train and ride after their purchase. Though easy to handle for general care, when asked to work under saddle, they became dangerous. The researchers concluded that the behaviour was caused by nervous system lesions which caused neuropathic pain (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8702524/?fbclid=IwAR0ygzx-PEGfgmLX04-MHUVBi88aQYGIND8jaUu1-MjamcFl-IrfdrvPRi8)
Nerves innervate muscles and other tissues and organs in the whole horse. A lack of innervation also results in lack of healthy blood/hypoxia and lymph flow and creates changes in development and health of the tissues and organs they serve. It is reasonable to assume that hoof and body development as well as organ function can be mildly or severely and or chronically impacted by nerve compression and lead to pathology, lameness and impaired function of digestion, performance, cognition, the senses and even premature death.
The cause of nerve compression can be varied and hard to recognise, and these could be congenital (eg ECVM, EMS, PSSM, ETC), and/or developmental through chronic tension, stress, training, inappropriate environmental stimulus, injury, ulcers, pain, dentistry or hoof balance.
Nerve compression might be alleviated through a therapeutic approach aimed at resetting the nervous system through activation of the parasympathetic nervous system via invitation, through release of fascia, muscles, correct skeletal alignment, movement and body work therapy.
The development of the horses muscles, hoof morphology, the limb and body posture, movement, response to stimuli, signs of pathology, behaviour and response to invitation to relax the sympathetic nervous system might highlight nerve compression, however a diagnosis should always be sought by a vet.
Hoof morphology can be negatively impacted by nerve compression from the body and upper limb. Unhealthy hoof morphology might also help create nerve compression and poor posture, so both should be considered and addressed for an integrative, whole horse approach to promoting wellness.
Signs associated with nerve compression and pathological compensatory posture
Recurring ulcers and GI dysfunction
Suspensory apparatus pathology
Explosive or difficult behaviour
Inability to utilise the stay apparatus/lock the carpus
Unhealthy proprioception
Reactive to touch
Difficult to shoe
Training difficulties, eg poor lead changes and transitions
Common posture and development anomalies associated with nerve compression
Weak shoulder muscles, especially suprascapular and infraspinatus
Overdeveloped (hypertrophied) ventral neck muscles especially brachiocephalicus
Underdeveloped pectoral muscles and other muscles associated with healthy thoracic sling development
Narrow chest with or without an obvious, protruding or dropped sternum
Ewe neck
Dipped back or roached back
Hollow wither pocket and/or lack of correct topline/back muscle development
Croup high
Straight gaskin
Elbow in or out
Stifle/knee turned in or out
Hypertrophy of the hamstring muscle group
Hypertrophy of iliopsoas muscle group (altering the pelvis angle, as well as the stifle and hock joint angle)
Weak stifle muscles (esp quadriceps)
Hyper dorsi flexion of the fetlocks (dropped pasterns)
Common pathological hoof morphology include low palmar or plantar P3 angles, caudal hoof collapse, long toe/low heel and hoof distortions
Asymmetries and weak thoracic slings are associated with hypertrophy of iliopsoas and camped under posture and are also indicative of low palmar P3 angles. Where there is compensatory posture and poor muscular development, the forces from the body in resting posture and during movement can negatively impact the hoof morphology and this in turn negatively impacts resting posture, movement and development. In addition, this can cause the horse to brace and over develop certain muscle groups such as sterno and brachiocepalicus . This is an inefficient way of moving and contributes to the horse utilising the hind quarters to effectively balance and lift the forehand, further contributing to loss of spinal integrity and core stabilising muscles.
The importance of healthy hoof ideals in supporting healthy posture and development and therefore preventing nerve compression
Without exception, and according to our documentation and experience, there is ALWAYS compensatory posture and development, and signs of nerve compression, in the presence of unhealthy hoof morphology. What came first isn't always clear. What IS clear is this... BOTH hoof and body need adequate and appropriate support in order to optimise the conditions to support healthy development of both hoof and body.
The overall lack of awareness of unhealthy 'ideal' or pathological hoof and posture in domestic horses is a REAL concern for us.... asking horses to perform or even exist where they have signs of nerve compression and/or hoof scores of less than 5/10 could and probably does lead to disease, lameness and premature death.
It is critical that owners and equine professionals (vets, farriers, trimmers, EP’s saddle fitters, body workers, dentists, behaviourists, etc) learn to recognise when a horse has adequate AND inadequate health for the role asked of it, even in the non-ridden pet or retired equine. This can be assisted by studying modern podiatry/farriery, using tools such as HoofmApp app in the field, and documenting to objectively monitor health and changes in response to changes in environmental stimulus and intervention used.
We invite you to document your horses hooves and posture, or those of your clients horses hooves and posture and use HoofmApp app or Metron-Hoof to help you assess objectively, and relate what you find to modern farriery and podiatry science. From this we would encourage you to provide a hoof score and ask whether the horse is being asked to work, perform or live beyond its hoof score. If the answer is 'yes' then question the environmental stimulus and hoof care intervention currently employed.
In order to recognise a problem, we first have to look. Be honest, be open and be non-judgmental, and always, try to be objective in your assessment.
Lazaris Nerve Release Technique
Lazaris Nerve Release Technique ™ is a proprietary training created by Celeste Lazaris centered around releasing nerve compressions within the horse with a specific focus on the brachial plexus and lumbosacral plexus.
Beccy is a certified Lazaris Nerve Release TM practitioner with Balanced Through Movement Method TM
Nerve Release can help alleviate symptoms associated with nerve compression, including:
Head Shaking Syndrome
Lack of Locking Carpal Joints (Becoming Over at the Knee)
Locking Stifle
Cross-Firing
Undiagnosed Lameness
Thoracic Sling Dysfunction
Topline Syndrome
Dangerous Behaviors
Spooky Behavior
Chronic Anxiety
Additional resources and assistance
We take an integrative and holistic approach to whole horse hoof and body health. We appreciate the relationship between body, limb and hoof and seek to address imbalances while positively influencing appropriate static and dynamic hoof balance and biomechanics.
We offer Lazaris Nerve Release Technique TM alongside our flagship Integrative Equine Podiatry Consult service or as a stand alone service. To learn more, including how to book Nerve Release, visit our page here
We also recommend you learn how to document horses hooves and body, whether you trim your own, your clients horses, are an equine professional (in any capacity/field) or simply want to track and monitor progress of your horses hooves and the impact their hoof care has on their posture.
Related articles:
https://www.holisticequine.co.uk/post/hoof-scoring-for-pro-active-preventative-whole-horse-hoof-care
Further information, recommendations and links
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Beccy Smith BSc ADAEP EBW
Diploma in Advanced Applied Equine Podiatry and now an Independent Integrative Equine Podiatrist, Consultant and Therapist. Certified Lazaris Nerve Release TM Practitioner
CEO and Founder of 100% Non-Profit Community Interest Company Holistic Reflections CIC
Holistic Reflections CIC – a 100% non-profit organisation promoting wellbeing and resilience in people, horses and the environment - for the benefit of all.