The hoof is the hard, keratinous capsule encasing the bones, soft tissues, and sensitive structures of the distal foot in horses, cattle, goats, and pigs. In horses it consists of three external regions: the wall, which bears weight and surrounds the foot; the sole, forming the concave underside; and the frog, the V-shaped rubbery pad at the center of the sole that absorbs shock and aids traction. All three regions are composed of keratin, the same fibrous protein that forms human fingernails, and all grow continuously from the coronary band—the ring of soft tissue at the junction of skin and hoof wall.
Internal structures protected by the capsule include the coffin bone (distal phalanx), the navicular bone, and the digital cushion. The coffin bone anchors to the inner surface of the hoof wall through interlocking laminae; compromised attachment from laminitis or white-line disease can cause the bone to rotate or sink within the capsule, producing severe lameness. The digital cushion, a fibrocartilaginous pad in the heel region, dissipates concussive forces with each stride and pumps blood back up the leg via venous pressure when the heel expands during weight-bearing. Proper hoof-wall integrity is therefore both a structural and circulatory requirement.
Routine trimming every six to eight weeks by a farrier maintains correct hoof-pastern angle and prevents the uneven growth that rotates joints and causes chronic lameness. Horses requiring corrective shoeing may be trimmed on shorter cycles. Nutritional status directly affects hoof quality: biotin, zinc, and methionine deficiencies produce brittle, cracking walls, while obesity combined with carbohydrate overload in the pasture is the leading dietary trigger of laminitis. A hoof abscess is the most common cause of sudden severe single-limb lameness and resolves rapidly once the pocket of infection is drained through the sole or white line.
Further Reading
For clinical detail on hoof-related lameness diagnosis and treatment: