400 THE COMPLETE GRAZIER. BOOK in. 



with the middle bone of the human palm, and is one of the most com- 

 pact bones in the horse. The splint bones correspond with the second 

 (forefinger) and fourth (ring-finger) bones in the human palm, and the 

 interosseous ligament between these and the cannon bone often becomes 

 ossified in old horses. The splints do not extend the whole length 

 of the cannon-bone ; each terminates in a button-like process. 



The solitary digit on the horse's fore limb (Fig. 92) represents the 

 middle finger of man, the three bones in each corresponding thus : 

 The pastern bone (os suifraginis) of the horse is equivalent to the 

 basal joint of man's middle finger, the coronet bone (os coronse) repre- 

 sents the middle joint, and the pedal or coffin bone (os pedis) of the 

 horse corresponds with the terminal joint of the human middle finger. 

 This last-named joint in man bears a nail, and similarly the coffin 

 bone in the horse is covered with a hoof, which is nothing other than 

 an enormously developed nail. 



At the back of the articulation of the pastern with the cannon bone 

 are two floating bones (sesamoids), which support the ergot and the 

 fatty cushion of the fetlock, the latter in some breeds being covered 

 with coarse hair like that of the tail. These " footlocks " are peculiar 

 to the horse, and vary in length and coarseness with the breed. 



The coronet bone, or small pastern, articulates above with the pastern, 

 and below with the coffin bone. At the back of the junction of the 

 coronet and coffin bones is another floating bone, the "navicular" 

 of veterinarians. It rests upon the fibrous elastic structure called the 

 plantar cushion, and is the seat of navicular disease. 



The nail (Lat. unguld) is developed not only upon the back but 

 upon the face and the sides of the coffin bone, so that the horse is 

 unguligrade. 



The hip girdle, or pelvic arch, consists of two equal pieces, called 

 the coxae, or ossa innominata, which, by their union with the sacrum 

 above, constitute the long cavity of the pelvis. Each coxa is an 

 irregular flat bone, directed obliquely from above tot below and from 

 before to behind. In the foetus, the coxa is formed of three distinct 

 bones, the ilium in the forward position, the ischium behind, and the 

 pubis below. The two pubic bones become united together to form 

 the symphysis pubis, whilst the tail hangs down between the two ischia. 

 The three bones ilium, ischium, pubis, all meet together in a great 

 cavity called the acetabulum, which looks downwards and outwards, 

 and into which the head of the femur, or thigh-bone, fits. The long 

 axes of the coxa?, or ossa innominata, which determine the relative 

 dimensions of the "quarters" in the horse, form an acute angle with the 

 vertebral column or backbone. 



The pelvis, as the bony basin of the hip girdle is called, is a simple 

 conoid cavity, in which the front aspect or inlet is far more extensive 

 than the hinder aspect or outlet. The pelvis of the mare exceeds that 

 of the horse in all dimensions, but the difference is most marked in the 

 transverse diameter. The inlet has a much greater circumference in the 

 mare. The floor of the mare's pelvis, moreover, is wide, and its bones 

 tend towards the same horizontal plane. In the mare the distance 



