PRINCIPLES OF VETERINARY SURGERY 365 



skin produced by constantly striking the fetlock with the opposite foot or 

 shoe becomes the seat of an infective inflammation which, by continuity of 

 tissue, extends into the synovials beneath. Accidental punctures with stable 

 forks are also often the starting point of these serious abscesses, in the 

 region of the fetlock. The tarsal sheath is generally infected from- kicks, 

 fork-punctures, etc. The aspirating needle inserted to evacuate the contents 

 of a thoroughpin has been known to carry infectious matter into the synovial 

 membrane, and thus set up a serious infective inflammation of the entire 

 sheath, that terminated by producing a prolonged suppurative process, an 

 acute obstinate lameness and a permanent blemish of the region. Tarsal 

 abscess may also occur from somewhat mysterious causes and in total ab- 

 sence of any perceptible breach in the skin. Severe straining of the part, 

 followed by the localization of pyogenic microorganisms in the injured focus, 

 offers the only rational explanation of some of the suppurative tarsal in- 

 flammations. In many instances the articular synovials are implicated either 

 primarily or secondarily. 



Symptoms. — The first evidence of the trouble is a more or less marked 

 lameness, tenderness of the region and a hot oedematous tumefaction spread- 

 ing in every direction from the trauma. Shortly the symptoms accentuate. 

 The lameness increases, the tenderness becomes more acute and the limb no 

 longer supports weight. If in a posterior extremity, the foot is held some 

 distance from the floor in a forward direction and is kept in constant motion 

 from the pain. When forced to move the patient will hop with difficulty on 

 the sound limb. In the anterior limb, the carpus is flexed, the elbow 

 dropped and the foot rests almost on its anterior face. When the morbid 

 process is located in the sesamoid, carpal or tarsal sheath, the oedema be- 

 comes more circumscribed, and the tenderness diminishes simultaneously 

 with the appearance of one or more fluctuating points somewhere along the 

 outlines of the sheath. When lanced, or allowed to burst spontaneously a 

 combination of liquid and coagulated synovia is discharged. This event, 

 contrary to the usual expectation, is not followed by any amelioration in 

 the lameness. The inability to support weight persists stubbornly and the 

 abscess openings continue to discharge the purulent synovia in somewhat 

 limited quantities. The openings dry up only to point elsewhere, until finally 

 the entire synovial membrane is destroyed by the inflammatory process. 

 Then, and then alone, will the period of improvement commence. As long 

 as there is a vestige of the infected, secreting membrane left, the abscesses 

 will continue to form. 



Gradually the patient begins to place the foot, heel first, to the floor, 

 and to show some slight inclination to bear weight when forced to walk. 

 For some weeks the leg is pushed well forward in walking. The stride is 

 exclusively anterior. The lameness becomes less and less during two or 

 three months, and finally ceases entirely, but the region remains hard, indu- 

 rated and tumefied. In some cases the lameness never entirely disappears 

 and the patient remains a more or less decrepit subject thereafter. These 

 symptoms apply equally to the abscess of the sesamoid, tarsal and carpal ap- 

 paratus, as the navicular sheath, owing to its confined position within the 

 hoof, presents a somewhat different aspect. The first evidence of the real 

 nature of the. trouble in this sheath is severe lameness accompanied with 

 synovial discharge from the nail puncture. At first the patient walks upon 

 the toe, but soon no weight is supported whatever, and ere long a marked 



