44 SKETCH OF THE ANATOMY OF THE HORSE. 



bone. The three muscles which bend the knee take their origin on the 

 back part of the humerus, just above the elbow joint, and are inserted 

 on the pisiform and splint bones. The two muscles which extend the 

 fetlock, pastern and pedal joints, run down the front of the fore-arm. One 

 of them has its origin at the head of the radius, and is inserted on the 

 front part of the long pastern bone. The other commences on the 

 humerus, just above the elbow joint, and ends on the front and upper 

 part of the pedal-bone. The muscles which flex the fetlock, pastern, and 

 pedal joints {the flexor muscles of the foot) and aid in bending the knee, 

 take their origin on the back part of the humerus, just above the elbow 

 joint, and proceed down the back of the fore-arm. A little above the 

 knee they are joined to their tendons (the back-tendons), which pass 

 through the sheath formed by the pisiform bone and the annular liga- 

 ment at the back of the knee. From there they run down the back of the 

 cannon-bone. The front one, which lies next the suspensory ligament, 

 goes over the sesamoid bones, which form a pulley for it ; down the back 

 of the pastern ; over the navicular bone, which also acts as a pulley ; and is 

 finally inserted on the base of the pedal-bone. The rearmost tendon, which 

 lies between the front one and the skin, forms a sheath for its fellow 

 at the back of the fetlock, and, dividing in two, is inserted on the short 

 pastern bone. There are two short muscles which assist the front one 

 of these two muscles, but which need no further allusion. As the 

 action of the suspensory and check ligament is closely connected with 

 that of the flexor muscles of the foot, it is appropriate to describe them 

 here. The suspensory ligament lies at the back of the cannon-bone and 

 between the two splint bones. It has its origin at the head of the cannon- 

 bone and lower row of the small bones of the knee. At about two-thirds of 

 the distance from the knee to the fetlock, it divides into two branches, 

 which are respectively inserted on the summits of the sesamoid bones. 

 They then extend downwards and forwards, and unite together, at the 

 front and about the middle of the pastern, with the tendon of the muscle 

 which extends the foot. The suspensory ligament is composed of white 

 fibrous tissue, with a few muscular fibres in it, and acts in supporting the 

 fetlock. It is generally considered to be inelastic, although Goubaux 

 and Barrier entertain the opposite opinion. They remark that " its 

 obscurely muscular structure, and the manner in which its fibres inter- 

 cross, render it a true elastic brace, which counteracts the effect of weight, 

 as long as they do not overcome the resistance and strength of the 

 tissues." In omnivorous and carnivorous animals this ligament is 

 represented by a muscle which has similar functions. The check ligament 

 has nearly the same origin as the suspensory ligament and joins the front 

 back-tendon, at a point about half-way down the cannon-bone. Its 

 office is to aid in supporting the fetlock and to relieve the muscles of the 

 tendon, with which it is connected, of weight. 



