52 



^VETERINARY SURGICAL OPERATIONS 



while the fluid is being aspirated. As the fluid, for reasons 

 hereafter mentioned, is caught in a pail it is important that 

 the patient be kept in one position during the entire opera- 

 tion. The twitch may be applied to the nose while the punc- 

 ture is made, in the exceptionally restive subject, but since 

 the pain amounts to nothing more than one sharp pang as the 

 trocar penetrates the skin, even this precaution is not often 

 necessary. Furthermore, the patient is usually too ill to 

 offer formidable resistance. 



Fig. 25— Seat of Operation and Method of Preventing Aspiration of Air 

 into the Thorax in Thoracocentesis. 



TECHNIQUE.— First Step.— Locating the Seat of Op- 

 eration. — The seat of operation is the flat part of the costal 

 surface behind and above the olecranon, on the right side of 

 the body. The puncture is usually made between the sixth and 

 seventh ribs and as near their distal terminations as possible. 

 It is not necessary t© count the intercostal spaces, in fact this 

 can not be done except when the patient is in exceptionally 

 poor flesh. (Fig. 25.) It is sufficient to trace an intercostal 

 space in the region as far down as its cartilage (if possible) 

 and then select a spot at the anterior border of the rib bound- 

 ing it posteriorly. When the animal is fleshy this may not 



