92 WOUNDS AND BRUISES. 



The special liability of a joint to suffer irreparable injury from the forma- 

 tion of pus in it is due (1) to the difficulty of effectively draining the 

 cavity ; and (2) to the fact that, to work properly, the articular surfaces 

 (p. 268) must be absolutely smooth and their lubricating apparatus in 

 perfect order ; failure in this mechanism being productive of disorganising 

 changes and chronic lameness. The smallest opening which will admit air, 

 or worse still, water or dirt, into the joint, may give rise to pus with its 

 attendant evil consequences. The health of a joint may, however, be 

 retained even after the free admittance of air into it, if prompt and strict 

 antiseptic precautions be adopted. 



In the case of an open joint in which the inflammation runs an unchecked 

 course, the articular cartilages and the ends of the bones which they cover, 

 become ulcerated ; the ligaments of the joint break down ; abscesses form 

 in the surrounding tissues ; and the whole part becomes disorganised, with 

 the result of a hopelessly stiff joint. There is always high fever, owing to 

 the fact that some of the microbes in the pus formed in open joints, secrete 

 jiroducts which act on the heat centres of the system. 



THE PRINCIPLES OF TREATMENT OF OPEN JOINT are as 



follows : — First, the synovial cavity must be thoroughly drained ; 

 secondly, the joint must be kept perfectly at rest; and firmly fixed ; 

 and thirdly, the discharges must be prevented from decomposing 

 by some efficient system of antiseptic treatment. 



TREATMENT. — If the injury be evidently superficial and there 

 be no flow of synovia, the wound can be treated as an ordinary one. 

 If, however, there be a discharge of synovia, it is safest to treat the 

 ca-se as one of open joint. First, make the part aseptic (not liable 

 to putrefy) by removing all dirt and other extraneous matter, and 

 by applying an antiseptic (p. 67), which may be done by syringing 

 the wound a few times with a 5 to 10 per cent, solution of hydrogen 

 peroxide in water ; chinosol (5 grains to half a pint) ; or creolin 

 01- carbolic acid in water (^ oz. to ^ pint). Secondly, protect it 

 from the entrance of putrefactive germs by several layers of anti- 

 septic wadding. If the wound is on or below the knee, it is v/ell 

 to apply cotton wadding (as in sprains, p. 44) over the antiseptic 

 wadding, beginning at the foot and continuing the bandaging for 

 a short distance above the wounded part. The object of checking 

 movement in the case of a leg, would be promoted by placing a 

 splint (Fig. 39) at the back of the limb ; care being taken that the 

 presence of the splint does not give rise to unequal pressure, which 

 would be apt to interfere with the circulation of the part. 

 "Veterinary instrument makers supply special splints, the use of 

 which would prevent movement in a fore leg, without the necessity 

 of bandaging. This object may also be attained by applying a 

 cantharides blister to tlie joints, to be made rigid for the time 

 being. For instance, in the case of open knee joint from a fall, 

 rub in a blister, behind the knee and pastern ; and about the 



