THE NECK. 161 



laryngeal nerve runs behind it and on the oesophagus near the trachea. Cutting it 

 will probably cause a permanent alteration in the voice. If the internal jugular vein 

 has been removed, as it may be on one side, but not on both, beneath it one is 

 liable to encounter the inferior thyroid artery below Chassaignac' s tubercle on the 

 sixth cervical vertebra, and further out the phrenic nerve on the scalenus anticus mus- 

 cle, and lower down the transverse cervical and suprascapular arteries. The inferior 

 thyroid veins usually run downward to empty into the innominate veins, but the 

 lower portion of the anterior jugular vein and the middle thyroid veins will probably 

 have to be ligated. The course of the various veins is quite irregular and large 

 venous branches may be encountered at any place. 



In the posterior cervical triangle the spinal accessory nerve must be avoided as 

 it runs down and back from the middle of the posterior edge of the sternomastoid 

 muscle. The external jugular, posterior jugular, transverse cervical, and supra- 

 scapular veins may all require ligation. Beneath the deep fascia (superficial layer) 

 are the descending or supraclavicular branches of the cervical plexus from the third 

 and fourth cervical nerves. Care should be taken not to mistake them for the 

 spinal accessory nerve. If the nerve has been divided it should be sutured together 

 again at the completion of the operation. It is hardly necessary to caution against 

 wounding the subclavian vein; it is in front of the anterior scalene muscle. The 

 artery is behind the muscle. Do not dig under it. It rests on the pleura, a wound or 

 tear of which may mean a septic pleurisy and death. In the angle formed by the 

 junction of the internal jugular vein and subclavian on the left side is the thoracic 

 duct. If wounded death may ensue through persistent leakage of lymph, but not 

 infrequently healing eventually occurs. Wounding of the corresponding lymphatic 

 duct on the right side is not considered so serious, the chyle being carried by the left 

 duct. The cords of the brachial plexus run down and across the posterior cervical 

 triangle above the subclavian artery, but a little care will enable one to avoid them. 

 This is one of the regions of the body in which exact surgery is essential. 



OPERATIONS ON THE AIR-PASSAGES. 



The pharynx may be opened just below the hyoid bone, subhyoidean pharyn- 

 gotomy. The larynx may be opened in the median line, thyrotomy. The crico- 

 thyroid membrane may be opened, laryngotomy. The trachea may be opened, 

 tracheotomy. 



Subhyoidean pharyngotomy is the entering of the pharynx by means of an 

 incision below the hyoid bone. This is an extremely rare operation. It may be 

 performed for the removal of foreign bodies or tumors. The incision may be made 

 just below the hyoid bone and parallel to its border. This will divide the com- 

 mencement of the anterior jugular vein, perhaps near the median line, perhaps toward 

 the side. A transverse vein usually runs from one anterior jugular vein to the other 

 across the median line at this point. Attached to the hyoid bone nearest to the 

 median line is the sternohyoid muscle, then farther out the omohyoid, and still farther 

 out the thyrohyoid. A small artery, the thyrohyoid, a branch of the superior thyroid, 

 or sometimes of the lingual, will be divided. 



The thyrohyoid membrane being incised, access is obtained to the fatty tissue 

 at the base of the epiglottis. If the incision is carried directly backward the epiglottis 

 will be cut through at its base. If, however, it is kept close to the hyoid bone and 

 made upward, the pharynx will be entered in front of the epiglottis and at the 

 root of the tongue. If the incision is carried too far toward the sides the superior 

 thyroid artery and even the external carotid itself will be cut; if carried too low down 

 on the thyrohyoid membrane, then the superior laryngeal artery and nerve may both 

 be wounded. Attention has already been called to the thyrohyoid branch. 



Thyrotomy is the division of the thyroid cartilage in the median line. The 

 sternohyoid muscles almost touch in the median line. The division should be 

 exactly in the median line. This will avoid wounding the anterior jugular veins. If 

 not in the median line the incision will wound one of the vocal cords. Impairment 

 of the voice certainly follows this operation; it is only performed for the removal of 

 foreign bodies or growths. 



