HOW CONCUSSION IS NEUTRALISED. 113 



joint is excessively flexed under the incidence of the body- 

 weight, these bones yield to a considerable extent. The sus- 

 pensory ligament, in common with the inferior and lateral 

 sesamoidean ligaments, and the two bands of the suspensory 

 which pass downwards and forwards (fig. 25, h^) to unite 

 with the extensor pedis tendon, assure to this joint a secure 

 position without any exertion of muscular strength, while 

 yet permitting the backward and downward movement of the 

 lower end of the metacarpal bone during movement. 



The anatomical peculiarities indicated greatly assist the 

 fetlock joint in neutralising shocks produced by the incidence 

 of the body- weight, so that in the normal position of the fet- 

 lock the force of impact is at least diminished by one-half, and 

 what remains is transmitted through the bones of the foot to the 

 hoof. As at the coronet joint the coronet bone is firmly attached 

 to the suffraginis, little movement can occur, and, therefore, little 

 diminution of shock. The coronet bone is connected directly 

 with the suffraginis, and indirectly with the sesamoid bones and 

 common extensor pedis tendon, an arrangement which prevents 

 displacement of the coronet joint under any ordinary load. 



So far as the dissipation of shock is concerned, the pedal 

 joint is much better arranged, its lower articular surface consisting 

 of two bones, the pedal and navicular. The mobility of this 

 joint is greater than that of the coronet joint, though not equal 

 to that of the fetlock ; on the other hand, the joint allows of 

 considerable lateral deviation. It is assisted in distributing 

 concussion, firstly, by the division of its articular surface into 

 two ; secondly, by the possibility of movement between the 

 pedal and coronet bones ; and thirdly, by the elastic nature of 

 the structures between the pedal bone and hoof. 



The pedal and navicular bones are connected by ligaments, 

 namely, two strong lateral ligaments, two suspensory ligaments 

 of the navicular bone (postero-lateral ligaments), which run 

 upwards somewhat spirally arranged, and the fibro-elastic 

 apparatus attached to the skin, referred to, p. 43 (fig. 27, e), 

 in addition to the ligaments connecting the navicular and 

 pedal bones (strahlbeinhufbeinbiinder) and the navicular bone 

 and lateral cartilages (strahlbeinhufknorpelbander). 



Broadly viewing, then, the collective ligaments of the three 

 joints of the foot, they are seen to lie chiefly on the posterior 



H 



