DISEASES OF THE JOINTS 419 



a prick, the pus formed may in many instances be very 

 near the capsular ligament of the articulation. Undei 

 such circumstances, unless there is a free and unhindered 

 flow of the pus from an outside opening, inroads will be 

 made by it upon the thin capsule. The latter is quickly 

 penetrated, and pus is admitted to the interior of the joint. 



In other cases infection of the joint may proceed from 

 within, from a poisoned state of the blood-stream. The 

 condition occurs, for instance, in bad attacks of laminitis. 

 We ourselves, too, have seen two cases where suppuration 

 of the pedal articulation occurred in the septic py?emia of 

 foals, a disease known commonly as ' joint-ill,' and charac- 

 terized by an infected state of the circulation. Cases have 

 also come under our notice where this condition has resulted 

 from slight injuries in the region of the insertion of the 

 extensor pedis inflicted by the animal himself when galloping 

 away. 



Perhaps, however, the most common cause of suppurative 

 arthritis in the foot is direct penetration of the articulation 

 in the case of pricks. The penetrating object is nearly 

 always dirty — bacterially dirty, at any rate — and sup- 

 puration only too readily commences. Even should such 

 a wound be inflicted by an aseptic body, infection would 

 quickly ensue as a result of the wound gathering dirt from 

 the ground, or even from admission to the joint of impure 

 and bacilli-laden air. 



Symptoms and Jjiagnosis. — This is one of the most serious 

 conditions we are called upon to face when dealing with 

 diseases of the foot, for in many cases it quickly ends in 

 exhaustion and death 'of the patient, while in even the 

 most favourable cases nothing better than a condition of 

 complete and bony anchylosis is to be expected. The owner, 

 therefore, should be warned accordingly. 



As in the other joint afiections, so here, we get all the 

 symptoms of acute febrile constitutional disturbance. The 

 pulse, the temperature, the respirations, and the general 

 haggard, ' tucked-up,' and distressed appearances of the 

 animal all tell too plain a tale. Our patient is in constant 

 pain, and the seat of the trouble is clearly enough shown 



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