TREPHINING THE NASAL FOSSAE. 37 



5. TREPHINING THE NASAt FOSSAE. 



Uses. Operations on the septum nasi, upon the tur- 

 binated bones, the removal of tumors or foreign bodies. 



Instruments. Same as for the frontal sinuses. 



Technic. The trephining is carried out by the method 

 described above, in the region of the nasal bone, close by 

 the median line of the face and according to indications at 

 any point from a level of the dotted line, SM, Plate III, to 

 the upper extremity of the false nostril. The operation 

 should be immediately against the median line since other- 

 wise the frontal or superior turbinated sinuses may be 

 opened, the highly vascular superior turbinated bone 

 wounded or an important inter-osseous artery in the nasal, 

 just above its union with the superior turbinated, bone as 

 shown in Plate VI, may be served. Special care is also 

 necessary that the trephining should not be carried too 

 deeply and that the osseous disc be carefully removed in 

 order to avoid wounding the highly vascular turbinated 

 bone, which lies in close proximity to it. The operative 

 area is narrow and the trephine used should not exceed 2 

 cm. in diameter. Whenever possible the operation should 

 be carried out on the standing animal which decreases the 

 hemorrhage and the danger from aspiration of fluids. The 

 hemorrhage may be further controlled in operations upon 

 the septum nasi and turbinated bones, by spraying the parts 

 with adrenaline chloride and cocaine. Even in the standing 

 animal, if extensive operations are to be carried out on the 

 very vascular septum nasi or on the turbine it is generally 

 advisable to preform trachetoray before trephining, and re- 

 tain the trachea tube in position until all danger has passed. 

 When the animal is confined in the recumbent pcsition the 

 patient's safety demands that tracheotomy be performed 

 before the operation is begun in almost all cases. Anaes- 

 thesia may be maintained in such cases by means of an 

 ordinary funnel with its tube bent at right angles and in- 



