LIGATION OF THE CAROTID ARTERY, 83 



needle, mouse-toothed forceps, ligation forceps, suture 

 material. 



Technic. The operation is possible on the standing 

 animal with the aid of cocaine or other local anaesthetic but 

 it is preferable to confine the patient in lateral recumbency 

 and anaesthetize. 



The operation is made at the same point as for phlebotomy 

 and the same cutaneous wound, a, Plate XIV, may be used 

 for this purpose. The incision should be at least 10 cm. 

 long extending through the skin, fleshy panniculus and 

 subscapulo-hyoideus muscles and then a passage forced with 

 the fingers, to the trachea. At the region of the neck 

 indicated, the carotid passes along the border between the 

 lateral and dorsal surfaces of the trachea, accompanied 

 dorsally by the vagus and sympathetic nerves and ventrally 

 by the recurrent. (In Figure 2, Plate XIV, the vagus 

 and sympathetic nerves, v and s, are pushed out of their 

 normal position and appear ventrally to the carotid. ) Pass 

 the index finger over and behind the carotid until the 

 trachea is reached, and encircling the in'ner and lower sides 

 of the artery, force a way through the surrounding areolar 

 tissue and draw the vessel out through the wound. As a 

 rule the carotid is still loosely surrounded by connective 

 tissue, which comes from the deep fascia of the neck and in 

 which also the three above mentioned nerves are found. 

 These nerves must be carefully separated from the carotid 

 and must on no account be included in the ligature. I,igate 

 the carotid twice with an interval of abbut 2 cm. between 

 the two ligatures and divide the artery midway between 

 them. The second ligature is necessary in order to prevent 

 hemorrhage from the distal end through collateral anasto- 

 moses and it is essential to sever the artery in order to avoid 

 its rupture by the stretching of the undivided carotid dur- 

 ing movements of the neck where the nutrition has been cut 

 off at the point of ligation. Provide drainage for the wound 

 and suture the muscle and skin. 



