THBCOCENTESIS 61 



fore the distended sac has entirely lost its elasticity. The old, 

 confirmed thoroughpin or wind-puff will not yield; the as- 

 piration of the fluid, the rest and the external irritants (blis- 

 ters) will not shrink up a sac thajt has maintained a certain 

 definite contour for years. In the more recent case, the 'as- 

 piration of the fluid every two weeks followed by the immedi- 

 ate application of a cantharides blister over the entire region, 

 will usually effect a permanent cure if persisted in for a period 

 of from three to six months. The aspiration should be re- 

 peated regularly as long as any synovia can be abstracted, 

 but the blisters should be omitted when the condition of the 

 blistered skin demands. The first three or even four treat- 

 ments may be discouraging, but thereafter, if the plan is per- 

 sistently carried out, the enlargement will gradually disap- 

 pear. In the work-horse, where scarring is not objectionable, 

 a good line firing may be substituted for the first blister. 

 Rest, or at least easy work, is essential to the success of the 

 treatment. 



EQUIPMENT.— 



1. Aspirating needle or small trocar and canula. 



2. Scissors and razor. 



3. A basin of antiseptic solution. 



The aspirating syringe often used for drawing out synovia 

 is not absolutely necessary, as synovia will flow out freely 

 enough without it until the sac is quite empty. 



RESTRAINT. — For the thoroughpin and wind-puff oper- 

 ations the standing position is the preferable one. The oppo- 

 site limb is held from the ground with the side line and the 

 twitch is applied to the nose By throwing all of the weight 

 upon the affected leg the distended sac is made tense and 

 prominent, and this facilitates both the penetration of the 

 needle and the flow of the fluid. Local -aneesthesia is not nec- 

 essary, because the pain is limited to a single pricking sensa- 

 tion, and this will pass unnoticed if the twitch is given an 

 extra turn as the needle penetrates the skin. 



TECHNIQUE.— First Step.— Disinfecting the Field.— 

 .The hair is clipped and shaved from a small spot about one 

 inch in diameter over the most prominent part of the enlarge- 

 ment. The denuded point is then submitted to a washing 

 with the antiseptic solution that will assure a clean skin. A 

 mercuric chloride solution, 1-500, applied with sharp fric- 

 tion, and then a rinsing with alcohol for a few moments is 

 the least that should be done in this direction. 



Second Step. — Inserting the Needle. — Before inserting 

 the needle it should have been sterilized by boiling or by a 



