1056 DISEASES OF THE FOOT. 



be fastened to the other limb of the same side by means of webbing. 

 Meantime the horse is anaesthetised. 



Two methods of procedure are at the operator's disposal, in the 

 first of which only a portion of the point of the frog is removed, in 

 the second the whole. The first method is often sufficient to disclose 

 the diseased tissues, and it has the advantage of producing a much 

 smaller, and therefore more rapidly-healing, wound than the second. 

 The sole, frog, and bars having been pared until they yield every- 

 w here to a slight pressure with the finger, a grooved director is passed 

 into the sinus, which is freely laid open to its extremity. Using the 

 curved knives shown in Fig. 569, the edges of the wound and 

 the plantar cushion are then removed so as to produce an elliptical 

 opening, at the base of which lies the perforans tendon. If the 

 superficial fibres of the tendon are necrotic the operator may confine 

 himself to removing such diseased tissue. But much more frequently 

 he finds it necessary to remove the entire thickness of the tendon 

 beneath the diseased spot and to extend his incision laterally so as 

 to operate in sound tissue. The portion of the navicular so exposed 

 may be curetted, if it show signs of disease. The wound is then 

 washed out with a disinfectant, dusted freely with iodoform, and 

 filled with masses of disinfected tow, or wood-wool. 



When carefully performed this partial operation is sometimes 

 rapidly successful, but on the whole it is apt to prove uncertain, and 

 to be followed by troublesome complications. The tendon sheath 

 becomes the seat of suppurating synovitis ; the navicular bone shows 

 superficial necrosis ; abscesses break in the flexure of the pastern, 

 and the remaining portion of the flexor tendon becomes necrotic. 

 In really grave cases where operation of this nature is necessary 

 it is usually best at once to perform the operation implicating both 

 sides of the frog. 



The preliminary precautions are as before mentioned. The foot 

 should be extended by an assistant, and the plantar cushion divided 

 transversely close to its base, with the double-edged curved knife 

 already referred to. The section should be at an oblique angle with 

 the general surface of the frog, and in such a direction that when 

 prolonged inwards it will meet the posterior edge of the navicular 

 bone. The half -detached fragment of the plantar cushion is then 

 grasped with forceps and freed from its lateral adhesions by two 

 cuts along the lateral lacunae of the frog. The deep face of the plantar 

 cushion is in contact with the flexor aponeurosis. 



Using both hands to steady the knife, the operator now divides the 

 aponeurotic portion of the tendon transversely close to the posterior 



