1082 



DISEASES OF THE FOOT. 



rise with great reluctance and a vast show of precaution, and when 

 again on their feet usually exhibit acute pain for a time. 



The severe pain sometimes forces the animal to lie continuously, 

 causing extensive bedsores, which may lead to the destruction of 

 the patient. In other cases, the os pedis perforates the horny sole, 

 septic inflammation of the sensitive structures of the foot sets in, pain 

 increases enormously, the animal is unable to stand, and death occurs 

 from exhaustion. 



In favourable cases the symptoms gradually decline and disappear 

 in from four or five to twelve days, but often the feet continue more 

 or less painful, though otherwise the patient may be out of danger. 

 Sometimes normal action is not regained before the end of a period 

 of rest'extending from six or eight weeks to three months. 



Pig. 577. — Longitudinal section of 

 hoof <>nc year after severe attack of 

 laminitis. 



Fig. 576. — Longitudinal section of 

 hoof three months after attack, a, 

 Pathologically modified horn of the 

 white line ; b, distortion of the horn 

 tubules in consequence of winking 

 of the os pedis. 



Displacement of the os pedis can be detected by the falling-in 

 round the coronet and depression of the sole. Once this has occurred 

 complete recovery is no longer possible ; the soles " drop," and 

 the animal ceases to be useful for work on stones or at a rapid pace. 



Horses with dropped soles exhibit a peculiar gait : the os pedis 

 being partly rotated around its transverse axis causes relaxation 

 of the flexor pedis perforans ; every time the animal extends the 

 limb, therefore, the coronet- joint shows abnormal dorsal flexion, 

 in consequence of which the heels come first to the ground. 



Differential diagnosis. The following are some of the conditions 

 which most closely simulate laminitis : — 



(1) Bruising of the sole in unshod horses ; this is detected by an 

 examination of the foot. 



(2) Muscular rheumatism. In this case the animal sometimes moves 

 as in laminitis ; the step is short and cautious, but the front limbs 



