THE TRACHEA 75 



transversely and cutting ofF the upper portion of the circumference of 

 the elUpse. 



The first four rings of the trachea are related laterally to the thyroid 

 body, and the thyro-laryngeal artery runs forwards and upwards between 

 this structure and the trachea. 



In connection with operations on the trachea it should be 

 remembered that the carotid artery crosses the tube obliquely upwards 

 and forwards, being below the trachea near the entrance to the chest, 

 and taking a more obliquely upward course than the trachea, reaches 

 its upper surface and at its termination, where it splits up into external 

 and internal carotids and occipital arteries, it is placed above the 

 cricoid cartilage. 



The common carotid is accompanied by the cord common to the 

 cervical portion of the sympathetic and the vagus nerves. This cord 

 lies above the artery, and running along the inferior aspect of the artery 

 is the recurrent laryngeal nerve. The jugular vein in the upper part of 

 the neck follows the upper border of the sterno-maxillaris muscle and 

 is here separated from the carotid by the subscapulo-hyoideus, but in 

 the lower part of the neck the vein, like the carotid artery, is lelated 

 to the trachea. 



Tracheotomy 



It is frequently necessary to perform the operation of tracheotomy, 

 thus providing a new respiratory opening for the relief of difficult 

 or obstructed respiration, which may be either temporary or permanent. 

 If the operation is for temporary relief, and the case is very urgent, failing 

 the insertion of a tube a slit is simply made through the skin and through 

 one or two tracheal rings, but if the difficulty is a permanent one the 

 relief provided must likewise be permanent, and in these cases a 

 tracheotomy tube is inserted to maintain the opening in the trachea 

 patent. 



In deciding the seat which should be adopted for the operation the 



