The equine hoof wall has a complex tubular structure, which extends across the stratum medium. In a healthy hoof, the tubules are straight, parallel to each other and descend at the same angle as the hoof capsule. On the bearing border surface of a trimmed hoof, they can be seen as a pattern of rings. Our human skin is an epidermal structure like the hoof, and yet skin does not have horn tubules within it. This article sets out to answer the simple question of why horn tubules exist within the hoof wall.