Sheared heels, also known as lateromedial imbalance, is an imbalance of the horse's heels, causing one of the heels (most frequently the medial one) to become more upright and shorter than the other, and strikes the ground before the other. Sheared heels is best seen when observed from behind the horse. When this imbalance occurs, it results in the opposite heel wall to expand and flare outwards. The difference is generally 0.5 cm (0.2 in) or more and is measured from the coronet to the ground or to the shoe. It is the result of repetitive disproportionate load to the horse's feet as a result of poor conformation or uneven trimming of the heels by the farrier.
Sheared heels is the most frequent reason for horses to develop quarter cracks and can also lead to compression of the heel and breakdown of sensitive laminae tissues, resulting in lameness.
Treatment of sheared heels is best achieved through the use of straight bar horse shoes, where the branches of the shoe are positioned and secured to where the hoof wall should ideally be, with the center line of the limb located over the center of the shoe. Through regular farrier work, and with each shoeing, the sole of the hoof should be brought back perpendicular to the long axis of the limb, until the ground impact is evenly distributed over both heels.