At the heels, the palmar/plantar portions of the walls bend inward sharply, following the external surface of the collateral grooves to form the bars. The lower surface of the hoof, from the outer walls and the inner frog and bars, is covered by an exfoliating keratinised material, called the 'sole'.
At the edges, the palmar/plantar surfaces of the walls curve inward sharply, following the external surface of the collateral grooves to form the bars. The lower surface of the hoof, from the outer walls and the inner frog and bars, is covered by a shedding keratinized material, called the 'sole'.