BACK- TENDONS. 37 



perforans tendon has been ruptured, the toe will tend to point upwards if 

 weight be put on the foot ; the cause evidently being that the direction of 

 the weight impressed on the limb falls behind the point of insertion of the 

 perforans tendon on the base of the pedal bone. Hence, it appears that the 

 toe of a sound horse is kept on the ground by the upward pull of the 

 perforans tendon successfully antagonising the downward pressure of the 

 weight borne by the limb. 



TREATMENT FOR SPRAIN OF THE SUSPENSORY LIGA- 

 MENT. — See page 44 et seq. 



Sprain of the Back Tendons and Check Ligament. 



Anatonm of bach tendmis and check ligament. — There are two back 

 tendons (Figs. 5 and 6) which originate from muscles that help to raise the 

 foot. From the knee, they run down behind the suspensory ligament, one 



Cannon bone 



Sesamoid bones 



Long pastern bone 



Short pastern bone "-^^ Navicular bone 

 Pedal bone — -r-'*^^^^' 



Fig. 9. — Rear view of bones of fetlOck and pastern. {After Chauveau.) 



overlying the other. The posterior tendon (the perforatus) forms a sheath 

 for the passage of the other (the perforans) at the back of the fetlock joint, 

 and becomes attached to the short pastern bone (Fig. 6). The perforans 

 tendon is joined halfway down the cannon bone by a powerful ligament 

 which originates at the head of that bone, and at the lower row of the 

 small bones of the knee, having almost the same origin as the suspensory 

 ligament (Fig. 6). This check ligament forms with the lower part of the 

 perforans tendon a strong brace for preventing undue obliquity of the 

 pastern ; its office being very similar to, though less effective than, that of 

 the suspensory ligament. The perforans tendon, after affording attachment 

 to the check ligament, passes over the two sesamoid bones, which act as a 

 pulley for it, then down the back of the pastern bones, over the third 

 sesamoid or navicular bone (Figs. 61 and 70), and is finally inserted on the 

 base of the pedal bone (Fig. 68). 



The parts at which the perforans tendon would be most likely to be 

 sprained, are its attachment to the pedal bone, and the point where it 

 passes over the sesamoid" bones. On carefully examining the perforatus — 

 the hindmost one of the two back tendons — we may conclude that it can 

 rarely become injured from excessive tension ; although it is specially liable 

 to suffer from blows inflicted by the hind foot. 



If the movements of the horse are examined in the gallop or 

 canter, it will be noted that, after the leading fore has been 



