The Horse's Feet and Their Care 169 



An important prerequisite to the detection and cure of disease 

 is a knowledge of the construction and function of the parts 

 which may be involved in the diseased process ; hence, first of all 

 the anatomical structure must be understood. 



The bones of the fetlock and foot constitute the skeleton on 

 which the other structures are built, and comprise the lower end 

 of the cannon bone (the metacarpus in the fore leg and the 

 metatarsus in the hind leg), the two sesamoids, the large pastern 

 or suti'ragius, the small pastern or coronet, the coffin bone or 

 ospedis, and the small sesamoid navicular bone. 



The cannon bone extends from the knee or hock to the fetlock, 

 is cylindrical in shape and stands nearly or quite perpendicular. 

 The sesamoids occur in pairs, are small, shaped like a three-faced 

 pyramid and are set behind the fetlock joint and the upper end 

 of the sutfragius, with the base of the pyramid down. The 

 suffragius is a very compact bone, set in an oblique direction 

 downward and forward, and extends from the cannon bone to the 

 coronet. The coronet is a short cube-shaped bone, set between 

 the suffragius and coffin bone in the same oblique direction. The 

 coffin bone forms the end of the foot and is shaped like the horny 

 box in which it is enclosed. The navicular bone is short, flat- 

 tened above and below, and is attached to the coffin bone behind. 



All of these bones are covei-ed on the surface with a cartilage 

 or incrustation which goes to make up the joints, w^hile the por- 

 tions between are covered with a fibrous membrane called the 

 periosteum. 



The points of the legs are of especial importance, since any in- 

 terference with their function very largely impairs the value of 

 the animal for most purposes. As the points of the foot and 

 ankle are at the center of greatest concussion they are the ones 

 most subject to injury and disease. 



There are three of these joints — the fetlock, pastern, and 

 coffin. They are made by the union of two or more bones held 

 together by ligaments of fibrous tissues, and are lubricated by a 

 thick viscid fluid, called synovia, w^hich is secreted by a special 

 membrane inclosing the joints. 



The fetlock joint is made by the union of the lower end of the 

 cannon bone and upper end of the large pastern bone, supplemented 



