048 



DISEASES OF THE FOOT. 



or excessive paring of corns may be followed by irritation, especially 

 if the roads are very dirty. Frostbite of the heels has been seen. 

 Chemical substances, like acids, employed by farriers in treating 



disease of the feet, sometimes 

 cause inflammation. But by 

 far the most frequent and im- 

 portant cause of acute inflam- 

 mation is infection with pus 

 cocci and other micro-parasites. 

 Normally, the soft parts are 

 protected by the horny wall, 

 but as soon as a fissure exists, 



Fig. sea-Vertical cross section of a foot seen in consequence either of pricks 

 from behind. To illustrate the structures in shoeing, picked-up nails, the 

 involved in surgical injuries of the foot. A, formation of sand-cracks, or 

 Coronet bone ; B, navicular bone ; C, pedal 



bone ; a. lateral cartilage ; b, anterior Separation of the wall, a way 

 portion of plantar cushion ; c, divided part is opened for infection, which 

 of flexor ; pedis perforans tendon ; rf, postero- is especially liable to OCCUr. as 

 lateral ligaments of navicular bone ; I, horn r J 



wall ; m, horn sole : n, white line ; o, horn the hoof is continually covered 

 fro S- with dirt containing infective 



substances. The course and consequences of the inflammation 



depend chiefly on the virulence of these organisms. 



Diagnosis. The presence of acute inflammation of the sensitive 



wall or sole may often be detected 



by the peculiar action of the lame 



leg. As pressure within the hoof 



is increased when weight is thrown 



on the limb, lameness is most 



marked during movement, especially 



over stones, though in the stall the 



foot is often rested and sometimes 



elevated. 



The foot must be carefully 



examined to detect deformities or 



fissures in the horn. (The manner 



of conducting this examination is 



fully described in Dollar and 



Wheatley's k ' Horse-shoeing and 



the Horse's Foot.") Palpation will detect increased warmth and 



pain. 



Prognosis. The degree of danger depends chiefly on the position 



and character of the inflammation. Whilst pododermatitis super- 



Fig. 561. — Vertical cross section of 

 foot seen from behind (this section 

 has been made nearer the heels than 

 Fig. 500). To illustrate the struc- 

 tures involved in surgical injuries 

 of the foot, a, Posterior part of 

 plantar cushion ; b, median ridge of 

 frog ; c, lateral cartilage ; rf. horn 

 wall ; e, lateral face of frog ; /, point 

 of union between the bars and frog. 



