166 MANUAL OF MODERN FARRIERY. 



and al)o\T. the heel of the coffin-bone, is placed a small 

 bone, called the navicular bone. (See plate 6, fig. 10, e.) 

 The use of this bone is to support and strengthen the union 

 between the lower pastern and the coffin-bone, and to assist 

 the flexor tendon in its action as it passes over it, in order 

 to be inserted into the bottom of the coffin-bone, and forme 

 a sort of joint with that tendon. The navicular bone is 

 subjected to much pressure, as is also this tendon ; and 

 besides, there is much plaj between them in the bending 

 and extension of the pasterns. 



Cause. — Like many other complaints of the horse, this 

 is often induced by sudden and violent exercise after the 

 animal has been allowed to stand in the stable inactive. 

 The parts not being for some time adapted to overstrained 

 action, there may be too much play between the bone and 

 the tendon, and by concussion of the parts the periosteum 

 or delicate membrane which covers the bones may be 

 bruised ; or the cartilage wf the bone may be inflamed, and 

 thus produce destruction of it, and cause a lameness of 

 the most painful description. From the navicular bone 

 being so obscurely situated, it is difficult to ascertain by 

 inspection when it is diseased. And this has puzzled many 

 to And out the cause of lameness emanating from it, and 

 has too often been attributed to the shoulder. Indeed 

 the action of the horse with this lameness has all the 

 appearance of being seated in the shoulder. Of late years 

 the attention of veterinary colleges has been particularly 

 directed to this point, and it has been found in numerous 

 cases of dissection that this is the seat of this lameness, 

 which has deceived and puzzled so many persons, both 

 learned and unlearned. The membrane covering the bone 

 has been found highly ulcerated, and the cartilage itself 

 completel}^ decomposed, and even the bones in a state of 



