144 ANATOMY AND PHYSIOLOGY OF THE HORSE’S FOOT. 
the horse’s foot rests on the ground, and which gives a 
cylindrical figure to the horny box. It is a circular band of 
horn, extending over the fore and lateral parts of the os pedis, 
originating at the coronet, where the hair-roots terminate, 
and descending in an oblique direction parallel to the face of 
that hone, to a certain distance beyond its lower margin. On 
lifting the foot and viewing its ground surface, we observe 
that the lower border of the wall projects more or less beyond 
the other parts, evidently making the first impression on the 
ground, and taking a large share in supporting weight and 
sustaining wear. Posteriorly, when it reaches the extremities 
of the wings of the os pedis, instead of its ends being con- 
tinued one into the other, so as to complete the circle, they 
suddenly become inflected, first downwards, then forwards and 
inwards, along the inner aspect of these wings, until they 
nearly gain the centre of the bottom of the foot, where they 
terminate. These inflections are not seen when the foot rests 
on the ground. 
Altogether, the wall may be said to form about two thirds 
of the entire hoof, or about eleven thirteenths of its plantar 
contour. 
With the object of describing this important division of the 
hoof more accurately, we may look upon it as having an ex- 
ternal and internal surface, an upper and a lower border, two 
angles of inflexion, and two centripetal prolongations, in- 
flexures or “bars,” as they are more usually designated. 
On a healthy foot — one which has not been exposed to the 
injurious influence of the farrier’s rasp or the groom’s hard 
water-brush — the external face is observed to be smooth and 
shining, as if varnished. Examining it closely, it is found 
to be made up of very fine, closely arranged parallel fibres, 
passing in a straight line from the upper to the lower border. 
Not unfrequently a series of faint undulating grooves and 
ridges, one above another, runs transversely across their direc- 
tion from one heel to the other. These circles or rings are 
more or less largely and peculiarly developed in certain 
diseases, and give the outer face of the wall a characteristic 
appearance. They are also due sometimes to change of food, 
locality, or increased activity in the secretion of horn, without 
disease being present. This face of the wall likewise shows 
various deformities and defects, the result of disease, accident, 
or mismanagement. 
The internal or posterior surface is that which is adapted 
to the laminated face of the os pedis,* and its whole aspect is 
# Stubbs, in his, for the age, magnificent ‘Anatomy of the Horse’ 
(London, 1766), aptly describes the laminae covering the pedal bone as “ a 
substance resembling the villous surface of a mushroom.” 
