THE TRACHEA j^ 



an upward direction, that part of the membrane being sUt which 

 connects the arytenoid cartilage with the base of the epiglottis, again 

 following the outline of the cartilage. This part of the incision cuts 

 through the left vocal cord. 



The cartilage is now freed from the membrane, and the joint 

 which its base forms with the upper aspect of the "bezel" of the 

 cricoid should be carefully located and disarticulated. 



The outer edge of the arytenoid is now seized and drawn gentlv 

 towards the operator whilst he dissects the cartilage free from the 

 structure which lies behind it, namely, the arytenoideus muscle. 

 During this part of the operation the terminal branch of the laryngeal 

 division of the thyro-laryngeal artery is severed, and the hemorrhage 

 from it must be immediately arrested by compression with a pair of 

 artery forceps. This process of dissection having been completed, the 

 cartilage is free and may be removed. 



The consecutive treatment is as in laryngotomy. 



THE TRACHEA 



The trachea is the middle or connecting piece of the respiratorv 

 tube. It is flexible and elastic, and is made up of a series of cartilaginous 

 rings, which however are not complete. A transverse section represents 

 the outline of the tube as being almost cylindrical, but not perfectly so 

 since it is slightly compressed from above to below. 



The rings are incomplete superiorly, and on this aspect of the 

 trachea the oesophagus, for the greater part in the cervical region, rests. 

 The anterior, or inferior, face is blended with the lateral surfaces, and 

 these are regularly rounded. These surfaces are crossed transversely bv 

 a series of grooves which correspond to the intervals between the 

 cartilaginous rings, the intervals between the cartilages being filled up 

 by an elastic membrane. 



The trachea commences at the cricoid cartilage of the larynx and 



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