Fig. 2.—A Hind Foot.
The Wall is that portion of the hoof seen whilst the foot rests upon the ground. It covers the front and sides of the foot. It extends from the coronet downwards and slightly outwards so that its lower circumference is greater than its upper. The front portion shows its greatest height and obliquity, diminishing in these respects as it passes backwards. At the heels the wall is turned in upon itself, and passes forward towards the centre of the foot until it becomes lost in the structure of the sole. These turned-in portions of the wall are called the bars, and serve two purposes; they increase the bearing surface of the wall, and by embracing a part of the sole on each side, they afford an increased solidity to the union of the wall with the rest of the hoof.
If we detach the wall its inner surface is seen to consist of a number of thin horny projections running parallel to each other from above downwards and forwards. These are called the horny laminæ. They number from five to six hundred and correspond to similar processes on the sensitive foot. ([Fig. 3]).
Fig. 3.—Half of a Hoof, showing the inside.
Round the upper circumference on the inside of the wall is a depression or groove presenting innumerable small pits or openings. This corresponds to a part of the sensitive foot called the coronary band, which will be noticed again.
A section of wall enables us to see variations in its thickness. ([Fig. 4]). It is thickest at the toe, becoming gradually thinner towards the heels; thus affording strength and solidity to resist wear at one part, as well as pliancy at another to ward off concussion.