Medio Lateral balance of the hoof

Introduction

Medio lateral balance is a foundational concept in farriery that directly influences equine soundness, joint stability and performance. It refers to the distribution of load between the medial and lateral sides of the hoof and limb throughout stance and locomotion. Although often oversimplified as symmetry of the hoof capsule, true medio lateral balance is a functional relationship that integrates conformation, muscular dynamics, hoof capsule geometry and movement patterns (Stashak and Gillet, 2011). Attaining and maintaining balance is critical because uneven loading contributes not only to hoof distortion but also to joint degeneration, soft tissue strain and compensatory gait abnormalities (Caster et al., 2012).

Achieving optimum balance is complicated by anatomical and conformational variations between horses. What appears visually symmetrical may not be functionally balanced, particularly if the underlying limb conformation or motion pattern is asymmetric (Clayton, 2013). Therefore, a farrier must go beyond superficial evaluation and develop a holistic understanding of how forces are transmitted through the limb. Medio lateral imbalance is seldom a primary disease but rather a contributing factor that can exacerbate existing pathology and inhibit recovery if not correctly managed (Van Heel et al., 2005). The role of the farrier is not simply to create a visually appealing hoof but to facilitate sustainable, efficient force distribution appropriate to the individual horse and its workload.

Understanding medio lateral balance requires an appreciation of normal anatomy, biomechanics and movement, and how these are influenced by both static and dynamic factors. This essay explores static and dynamic assessment methods, conformational faults that predispose to imbalance, radiographic evaluation, focused assessment of forelimbs and hindlimbs, associated pathologies, corrective trimming strategies and shoeing options. Throughout, evidence based practice is integrated with clinical experience, drawing on peer‑reviewed research and authoritative texts in equine podiatry.

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Static Assessment of the Horse

Static assessment is the initial step in evaluating medio lateral balance and must be undertaken with the horse standing square on a firm, level surface. Prior to handling the feet, an overview of posture provides insight into how weight is distributed throughout the body. Observations are made from the front, side and rear of the horse, noting limb alignment, hoof placement and stance width (Caldwell and Greene, 2014). Horses that stand base narrow or base wide often have inherent loading biases that influence distal limb mechanics (Ross and Dyson, 2011). Similarly, deviations such as toe in or toe out affect how the foot contacts the ground and may be evident only when the horse is observed from multiple angles.

When viewed from the front, the limb should ideally align vertically from shoulder to fetlock and pastern, terminating in the hoof capsule centred beneath the limb (Moyer and Stashak, 2006). Although perfect alignment is uncommon, significant deviation of limbs medially or laterally often reflects compensatory posture or underlying skeletal asymmetry (Hood, 2003). Observing the height and symmetry of the coronary band is essential. A higher medial band compared to the lateral band is frequently associated with prolonged increased loading on the medial side of the foot and subsequent asymmetric wall growth (Stashak and Gillet, 2011).

Static examination of the hoof itself continues once the foot is lifted. Heel height, width and orientation are compared. Uneven heels indicate asymmetric loading patterns and are often accompanied by compensatory changes such as underrun heels or flared walls (Moyer, 2008). Assuming there are no conformational defects, the long axis of the limb should be used to determine whether heel heights are of a similar length. This results in using a 90 degree evaluation of the heels against the long axis in order to determine the balance of the hoof.  To assess medio-lateral balance through the long axis, the farrier should first position themselves in front of the horse, facing the limb, ensuring the horse is standing square and relaxed. The forelimb is lifted in a straight line, keeping the elbow close to the horse’s body to avoid rotation of the limb.

The farrier supports the limb just above the fetlock or at the pastern, allowing the foot to hang naturally without twisting or pulling it medially or laterally. The toe should point directly forwards, aligning with the long axis of the limb from the shoulder, through the elbow, knee, cannon and fetlock.

Farrier holding the limb freely in alignment with the long axis of the limb.

With the limb held steady, the farrier visually assesses whether the hoof capsule is symmetrical either side of this long axis, comparing medial and lateral wall height, heel height, and overall hoof mass distribution. Any deviation of the hoof away from the limb’s long axis may indicate medio-lateral imbalance, whether conformational or acquired. Should there be any medial or lateral lower limb deviations, then the last point of deviation should serve as the reference point for evaluation against the heel heights. The hoof wall thickness should be palpated and visually examined for flaring, which is often most pronounced on the overloaded side due to increased eccentric forces (Bowker and Linder, 2016). The solar surface is inspected for depth of concavity, sole callus distribution and relative depths at the medial and lateral quarters and heels. Callus formation is especially telling, as callus develops in response to habitual weight bearing and reflects chronic loading patterns (Van Heel et al., 2005).

Static assessment should also include evaluation of the soft tissue structures surrounding the foot. Thickening of the collateral ligaments, asymmetry of the digital flexor tendon sheath or swelling of the coronet band may all indicate chronic imbalance and compensatory loading (Walmsley et al., 2009). Without a thorough static assessment, dynamic issues may be misinterpreted, leading to inappropriate corrective strategies.

Dynamic Assessment and Functional Balance

While static assessment provides critical baseline information, dynamic assessment reveals how the horse actually loads and uses the limb during movement. A foot that appears well balanced at rest may behave differently in motion, particularly under the influence of speed, surface variability and training demands. Observation of the horse at walk and trot, both in straight lines and circling in both directions, is essential to understanding functional loading patterns (Clayton, 2013).

When assessing motion, the farrier should first observe the horse walking towards and away from the observer. The orientation of the hoof at landing provides clues to medio lateral balance. Ideally, the foot should make relatively flat contact with the ground. However, consistent medial or lateral first contact indicates functional imbalance and altered force distribution (Stashak and Gillet, 2011). Paddling, winging or cross‑firing on turns may also reflect rotational deviations that influence how the foot loads during stance (Holcombe and Shaffer, 2008).

At the trot, asymmetries become more pronounced due to increased impact forces and reduced time spent in stance. The farrier should watch for signs of uneven breakover. Breakover that is delayed on one side of the foot increases the duration of loading and subsequently the force transmitted through distal joints and soft tissues (Clayton, 2013). This often results in a characteristic rolling over the medial or lateral quarter during breakover, depending on which side is overloaded.

Tracking patterns on a circle are particularly informative because they amplify proprioceptive and biomechanical challenges. When a horse moves on a circle, the inside limb typically bears a greater proportion of vertical force while the outside limb experiences increased lateral force components (Merkens and Schamhardt, 1988). Horses with pre‑existing medio lateral imbalance tend to struggle more on the inside of the circle, exhibiting asymmetrical landing patterns, shortened strides or altered head carriage as compensatory mechanisms (Van Heel et al., 2005).

Dynamic assessment should also consider wear patterns on previously applied shoes, as these provide historical evidence of loading. Excessive wear on one branch relative to the other is often aligned with the side of increased force transmission during stance and can guide corrective trimming (Bowker and Linder, 2016). Taken together with live observation, these wear patterns help distinguish between transient gait irregularities and chronic imbalance.

Conformational Faults That Lead to Medio Lateral Imbalance

A key factor influencing medio lateral balance is conformation. The way a limb is built fundamentally affects how forces travel through bones, joints, tendons and ultimately the hoof capsule. Angular limb deviations, including carpal valgus and varus, influence load distribution. Carpal valgus, where the distal limb deviates laterally relative to the proximal limb, often results in increased medial loading at the hoof due to the altered line of force (Ross and Dyson, 2011). Conversely, carpal varus can lead to increased lateral loading.

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Rotational conformations, such as toe in (medial rotation) and toe out (lateral rotation), further influence how the hoof contacts the ground. Horses that toe in tend to land medial first and often develop increased loading of the lateral hoof wall from secondary loading (Hood, 2003). In contrast, toe out conformation typically results in lateral first contact and increased stress on medial structures from secondary loading. Attempting to level the hoof visually without addressing the underlying rotational component can force the foot into an unnatural functional alignment, increasing strain on joints and soft tissues above the hoof (Clayton, 2013).

Base narrow and base wide conformations similarly alter force transmission. A base narrow horse tends to load the lateral hoof wall more heavily, while a base wide stance typically increases medial load. These conformational variations often interact with other traits, such as pastern angle and shoulder slope, resulting in complex patterns of imbalance that cannot be corrected solely by trimming or shoeing (Van Heel et al., 2005).

Conformation also influences muscle development and neuromuscular control. For example, horses with significant rotational deviation often develop compensatory muscular asymmetry that further reinforces the imbalance (Walmsley et al., 2009). The farrier must recognise that while trimming and shoeing can mitigate the effects of conformational faults, they cannot fully correct structural abnormalities. Instead, strategies focus on working within the horse’s natural biomechanical limits to reduce excessive stress.

The Use of Radiography in Medio Lateral Assessment

Radiography is an indispensable diagnostic tool in the farrier’s armamentarium, particularly in cases where external assessment is misleading due to hoof capsule distortion or chronic adaptation. Internal structures, including the distal phalanx and joint spaces, cannot be accurately assessed solely by external palpation or observation (Van Heel et al., 2005). Radiographic evaluation allows visualisation of the relationship between the distal phalanx and the hoof capsule and facilitates objective assessment of medio lateral balance.

The dorsopalmar (forelimb) or dorsoplantar (hindlimb) radiographic view is especially useful for assessing whether the distal phalanx is level within the hoof capsule (Jeffcott and Dalin, 1993). When asymmetrical solar margin heights are evident, this often reflects sinking or rotation of the distal phalanx mediated by uneven force distribution. Without radiographs, such distortion might be masked by adaptive hoof growth or compensatory tissue changes.

Radiography also aids in evaluating sole depth and hoof wall thickness on both sides of the foot. Accurate assessment of these parameters is essential prior to trimming excess horn, as over trimming in an attempt to correct imbalance can lead to discomfort or expose sensitive structures (Moyer and Stashak, 2006). In some cases, radiographs reveal internal pathology such as subchondral bone changes, joint space narrowing or collateral ligament abnormalities that influence how balance should be achieved and maintained (Caldwell and Greene, 2014).

The use of serial radiographs over time can help monitor how the foot responds to trimming and shoeing changes, allowing incremental adjustments. Collaboration between farrier and veterinarian in interpreting these radiographs enhances decision‑making, ensuring that interventions are guided by structural integrity and long‑term soundness rather than superficial hoof appearance alone.

Learn more about radiography of the hoof at the link below:

https://www.thefarrier.co.uk/post/understanding-how-radiographs-can-help-your-horse-s-feet

Assessment of the Forelimb

The forelimbs bear approximately sixty percent of the horse’s body weight during standing and support significantly greater loads during locomotion, particularly at the trot or in performance activities (Stashak and Gillet, 2011). This increased loading makes the forelimbs especially sensitive to medio lateral imbalance. Assessment begins with a proximal to distal approach, examining the shoulder, elbow, carpus, fetlock and hoof.

Proximal limb alignment influences distal loading. For example, a medial deviation at the carpus (valgus) often leads to increased medial hoof wall load. Conversely, lateral deviation (varus) is associated with lateral overload. Carpal abnormalities also influence knee flexion mechanics, which can cascade into altered fetlock mechanics and uneven foot loading (Ross and Dyson, 2011).

The hoof itself must be evaluated for subtle cues that influence balance, including the slope of the dorsal wall, length of the medial and lateral walls and integrity of the heel buttresses. Forefoot imbalance often manifests as differential heel height or asymmetric wall flaring at the quarters. These findings, combined with dynamic assessment, guide trimming and shoeing decisions that aim to redistribute load and encourage more symmetrical gait mechanics.

To assess medio-lateral balance through the long axis, the farrier should first position themselves in front of the horse, facing the limb, ensuring the horse is standing square and relaxed. The forelimb is lifted in a straight line, keeping the elbow close to the horse’s body to avoid rotation of the limb.

The farrier supports the limb just above the fetlock or at the pastern, allowing the foot to hang naturally without twisting or pulling it medially or laterally. The toe should point directly forwards, aligning with the long axis of the limb from the shoulder, through the elbow, knee, cannon and fetlock.

With the limb held steady, the farrier visually assesses whether the hoof capsule is symmetrical either side of this long axis, comparing medial and lateral wall height, heel height, and overall hoof mass distribution. Any deviation of the hoof away from the limb’s long axis may indicate medio-lateral imbalance, whether conformational or acquired.

Assessment of the Hindlimb

The hindlimbs are the powerhouse of the horse, primarily responsible for propulsion rather than static weight bearing. As a result, medio lateral imbalances in the hindlimbs influence push‑off mechanics, thrust efficiency and straight‑line movement. The hindlimb should be evaluated from the pelvis through to the digits, with particular focus on the alignment of the stifle and hock.

Viewed from behind, the farrier should evaluate whether the horse is cow hocked, bow hocked or base narrow. Cow hocked conformation, where the hocks are closer together and the lower limb deviates laterally, often results in increased lateral load in the hindfoot, whereas bow hocked horses typically overload the medial side (Hood, 2003). Base narrow stance in the hindlimbs creates a different set of loading challenges, frequently resulting in unstable and uneven foot placement.

Assessment of the proportions of a hind hoof

The hock joint is an important focal point because it is subject to significant force transmission during propulsion. Asymmetric hock motion, swelling or limited range of motion may be secondary to uneven hindfoot loading and should be investigated in conjunction with hoof assessment (Moyer, 2008). The hind hoof should be examined for quarter and heel symmetry, sole depth and wall integrity. The orientation of the hoof relative to the limb axis provides insight into functional mechanics, particularly how the horse initiates push off during gait.

To assess medio-lateral balance of the hind hoof through the long axis, the farrier stands slightly to the side of the horse, facing the hind limb, maintaining close body contact for safety. The hindlimb is lifted straight back from the hip, not pulled out to the side, to avoid inducing rotation within the limb.

The farrier supports the limb just above the fetlock, allowing the cannon bone to remain vertical and the foot to hang naturally. Care is taken to ensure the limb is not abducted or adducted, as this would distort the true long axis. With the limb held steady, the farrier visually aligns the long axis from the point of the hock and down the cannon, assessing whether the hoof capsule sits evenly either side of this axis. Medial and lateral wall height, heel height and hoof symmetry are compared.

Farrier assessing a hind hoof

Dynamic observation of the hindlimbs is particularly valuable, as imbalance often becomes apparent only under load. A horse that pushes unevenly through one side of the hindfoot typically demonstrates shortening of stride on the affected side, difficulty maintaining straightness or altered pelvic motion (Clayton, 2013). Identification of these functional signs allows the farrier to tailor trimming and shoeing interventions that support balanced propulsion.

Pathologies Associated with Medio Lateral Imbalance in the Forelimb and Hindlimb

Persistent medio lateral imbalance predisposes horses to a range of pathological conditions in both forelimbs and hindlimbs. In the forelimbs, chronic uneven loading of the foot increases stress on the collateral ligaments of the coffin joint and distal interphalangeal joint, contributing to ligament desmitis and degenerative joint disease (Caster et al., 2012). Uneven forces may also accelerate wear of articular cartilage, particularly on the overloaded side, predisposing to osteoarthritic change (Walmsley et al., 2009). The navicular apparatus is another structure vulnerable to imbalance. Increased load on one side of the foot amplifies compressive forces within the navicular bone and associated bursa, often resulting in pain, reduced performance and gait abnormalities (Jeffcott and Dalin, 1993).

Collateral ligament strain arising from a medio-lateral imbalance

In the hindlimbs, medio lateral imbalance is frequently associated with proximal suspensory desmitis. Unequal loading of the hindfoot places disproportionate strain on one branch of the suspensory ligament, leading to microtrauma and pain (Ross and Dyson, 2011). Asymmetric forces through the hock increase the risk of osteoarthritis in the tarsal joints and limit normal range of motion. Hindlimb imbalance also affects the pelvis and sacroiliac region, as altered push off patterns create asymmetrical force vectors that travel proximally (Clayton, 2013). Over time, these compensatory patterns result in muscle asymmetry, reduced engagement and a decline in overall performance.

Soft tissue structures, including tendons and ligaments throughout the limb, adapt to repetitive uneven loading by altering fibre alignment and tension. Initially, these adaptations may sustain function, but over time they increase injury susceptibility and reduce resilience (Bowker and Linder, 2016). Recognising these pathologies and understanding their relationship with medio lateral imbalance underscores the importance of early and appropriate intervention rather than management of advanced disease states.

Trimming Techniques to Overcome Medio Lateral Imbalance

Effective trimming strategies for addressing medio lateral imbalance require precision, an understanding of functional anatomy and an appreciation for incremental change. The primary goal of trimming is to establish a stable, supportive base that encourages even force distribution through the foot within the horse’s conformational limits. This begins with accurately identifying the true weight bearing structures on the solar surface, particularly the sole callus and heel buttresses (Van Heel et al., 2005).

When correcting imbalance, the farrier must determine how much horn to remove from the overloaded side and how much support to retain on the underloaded side. In chronic cases, aggressive removal of excess wall or heel on the overloaded side can lead to discomfort and compensatory gait changes. A gradual correction over multiple shoeing cycles allows soft tissues and joints to adapt to changes in loading without disruption (Moyer, 2008). At each trimming session, the farrier must assess whether the planned changes improve function and comfort based on static and dynamic observations.

Preservation of sole depth is critical, especially on the overloaded side, because excessive reduction can compromise protection of internal structures and lead to soreness. Trimming should aim to establish mediolaterally balanced breakover. Easing breakover on the overloaded side can reduce leverage and shorten the duration of force transmission, reducing stress on joints and ligaments (Clayton, 2013). This can involve adjusting the dorsal wall or quarters in a way that facilitates efficient push off while maintaining structural integrity.

Frequent reassessment during the trimming process is essential. Placing the trimmed foot on a flat, level surface allows the farrier to visually and tactilely evaluate whether the foot now loads more evenly. This ongoing feedback loop guides decisions about how much further adjustment is needed and allows the farrier to tailor each session to the horse’s response.

Shoeing Options Used to Correct Medio Lateral Imbalance

Shoeing provides additional corrective tools when trimming alone is insufficient to achieve functional balance. One common shoeing approach is the use of a level shoe with precise foot preparation. Minor imbalances may be managed by adjusting hoof wall height and ensuring even heel support. In cases where one side of the foot is consistently overloaded, the farrier may fit the shoe with slightly increased width in relation to the hoof shape on the overloaded side to increase ground contact and encourage more even weight distribution (Stashak and Gillet, 2011).

Specialist shoes are often indicated for more complex or pronounced imbalances. The spiral lift shoe is one such design that applies a gradual change in height across the foot, allowing controlled redistribution of forces from one side to the other without large abrupt changes (Caldwell and Greene, 2014). Spiral lift shoes are particularly useful in horses with angular limb deviations because they allow the corrective force to be applied in a manner consistent with the limb’s functional axis. Adjusting the degree of elevation over successive shoeing cycles permits gradual adaptation and reduces the risk of discomfort.

Bar shoes provide another valuable option, particularly for horses with significant medio lateral instability or associated soft tissue injury. Straight bar and egg bar shoes increase the surface area of support, stabilising the hoof capsule and reducing independent movement of the heels and quarters (Bowker and Linder, 2016). The increased contact surface helps to distribute forces more evenly, particularly when the hoof walls are weak or quarter cracks are present. Bar shoes can also reduce peak pressures on the overloaded side, improving comfort and promoting symmetrical loading. A heart bar shoe may be considered where frog support is desirable, and the frog is healthy enough to bear load. By transferring some weight from the heels to the frog, the imbalance can be reduced. This option requires a high level of skill, as incorrect frog pressure can exacerbate pain rather than relieve it.

Pads may also be used to fine tune balance, particularly when sole depth is limited. Graduated frog support pads allow subtle adjustment without excessive horn removal and provide additional protection during periods of transition (Van Heel et al., 2005). The leather and/or synthetic properties of the pad can provide anti concussion to the hoof and coffin joint, especially when combined with a soft setting impression material compound underneath the pad. Graduated pads can also be modified on a grinder to create a spiral lift and help to establish a level foot fall, in some cases this spiral can be gradually reduced as the medio lateral balance improves and the hoof begins load evenly.

Spiral medial lift using a pad to establish level footfall.

Conclusion

Medio lateral balance is a dynamic and multifaceted aspect of farriery practice that plays a central role in equine soundness, biomechanics and performance. It encompasses more than visual symmetry of the hoof capsule, requiring a thorough understanding of anatomy, biomechanics, conformation and movement. Static and dynamic assessment, combined with radiographic evaluation where appropriate, provide the foundation for accurate diagnosis and tailored corrective strategies.

Conformational abnormalities may limit the degree to which perfect balance can be achieved, yet significant improvements can be made that reduce strain, enhance comfort and prolong the working life of the horse. Effective management of medio lateral balance integrates thoughtful trimming, appropriate shoeing and ongoing evaluation of function. By appreciating the complexity of forces acting within the foot and limb, the farrier supports long term musculoskeletal health and optimal performance.

References

Bowker, R.M. and Linder, K.E. (2016) The Hoof: Therapeutics and Lameness. 2nd edn. Raleigh: The American Farrier’s Association.

Caldwell, F.J. and Greene, S.A. (2014) ‘Farriery and lameness management in the performance horse’, Equine Veterinary Journal, 46(3), pp. 300–308.

Caster, W.O., McIlwraith, C.W. and Reiser, R.F. (2012) ‘Biomechanics of the equine foot: Implications for therapeutic trimming and shoeing’, Journal of Equine Science, 23(2), pp. 45–57.

Clayton, H.M. (2013) The Dynamic Horse: A Biomechanical Guide to Equine Movement and Performance. Edinburgh: Elsevier.

Holcombe, S.J. and Shaffer, J.R. (2008) ‘Comparison of movement asymmetries in horses’, Veterinary Journal, 176(1), pp. 57–68.

Hood, D.M. (2003) Corrective Farriery. London: Blackwell Publishing.

Jeffcott, L.B. and Dalin, G. (1993) Radiography of the Horse. 3rd edn. Sydney: University Press.

Merkens, H.W. and Schamhardt, H.C. (1988) ‘Forces and impulses in the limbs during circular motion’, Equine Veterinary Journal, 20(1), pp. 32–36.

Moyer, W. (2008) Principles of Equine Podiatry. Winchester: Farrier Publications.

Moyer, W. and Stashak, T.S. (2006) ‘Static and dynamic assessment of the horse’, The Veterinary Clinics of North America: Equine Practice, 22(2), pp. 239–255.

Ross, M.W. and Dyson, S.J. (2011) Diagnosis and Management of Lameness in the Horse. 2nd edn. St Louis: Saunders.

Stashak, T.S. and Gillet, L.E. (2011) Adams’ Lameness in Horses. 6th edn. Ames: Wiley‑Blackwell.

Van Heel, M.C.V., Sloet van Oldruitenborgh‑Oosterbaan, M.M. and Van Weeren, P.R. (2005) ‘Biomechanical analysis of hoof balance’, Equine Veterinary Journal, 37(4), pp. 383–388.

Walmsley, J.P., Williams, J.L. and Smith, R.K.W. (2009) ‘Soft tissue adaptations to chronic limb imbalance’, Veterinary Journal, 179(2), pp. 251–259.