THE NECK. 145 



superficial, being covered by the skin, superficial fascia, platysma, deep fascia, and 

 overlying edge of the sternomastoid muscle. It is to be reached through an incision 

 5 cm. in length along the anterior edge of the sternomastoid muscle in a line from 

 the sternoclavicular joint to midway between the angle of the jaw and the mastoid 

 process. The middle of the incision is to be opposite the thyrohyoid membrane. 

 The bifurcation of the common carotid artery is an important landmark. 



The superior thyroid artery is given off at the very commencement and some- 

 times even comes from the common carotid just below. The ascending pharyngeal 

 is the next branch, about i cm. above the superior thyroid. It comes off from the 

 deep surface of the artery ; almost opposite to it and in front is the lingual. It will 

 thus be seen that the distance between the lingual and the superior thyroid, where 

 the ligature is to be placed, is quite small. The superior thyroid is about opposite 

 the upper border of the thyroid cartilage, while the lingual is opposite the hyoid 

 bone. Beneath the artery is the superior laryngeal nerve, but it is not liable to be 

 caught up by the needle in passing the ligature because it lies flat on the constrictors 

 of the pharynx and is apt to be a little above the site of ligation. 



The veins are the only structures liable to cause trouble. They are superficial 

 to the arteries. On account of their irregularity more may be encountered than is 

 expected. The superior thyroid and lingual veins both cross the artery to empty 

 into the internal jugular. The facial vein is also liable to be met, as the facial artery 

 frequently springs from a common trunk with the lingual. The communicating 

 branch between the facial and external jugular vein is another one that should be 

 anticipated. These veins, when it is possible, are to be hooked aside; otherwise 

 they are to be ligated and cut. Great care should be taken not to mistake a vein 

 for the artery. It might appear an easy matter to readily recognize the artery and 

 distinguish between it and the veins, but this is not always the case in the living 

 subject. The veins may have some pulsation transmitted to them from the adjacent 

 arteries and the artery may temporarily have its pulsations stopped by pressure from 

 the retractors. The living artery touched by the finger seems soft and does not give 

 the hard, resisting impression felt in palpating the radial in feeling the pulse. The 

 difference in thickness of the coats is also sometimes not apparent at a first glance. 



The ligature is to be passed from without inward so as to guard against wounding 

 the internal carotid. 



Ligation of the Superior Thyroid Artery. The superior thyroid is the first 

 branch of the external carotid and is given off close down to the bifurcation or even 

 from the common carotid itself just below. It lies quite superficial but of course 

 beneath the deep fascia. At first it inclines upward and then makes a bend and goes 

 downward to the thyroid gland. It gives off three comparatively small branches, 

 the hyoid along the lower border of the hyoid bone, the sternomastoid to the muscle 

 of that name, and the superior laryngeal to the interior of the larynx. The larger 

 portion of the artery goes downward to supply the thyroid gland and muscles over 

 it, therefore the artery is to be looked for at the upper edge of the thyroid cartilage, 

 and not near the hyoid bone. The incision is the same as for ligating the external 

 carotid low down, viz. , 5 cm. along the anterior edge of the sternomastoid muscle, its 

 middle being opposite the upper edge of the thyroid cartilage. Veins from the thyroid 

 gland superior thyroid will probably cover it. After the deep fascia has been 

 opened, the external carotid is to be recognized at its origin from the common carotid 

 and then the superior thyroid artery found and followed out from that point. The 

 ligature is to be passed from above downward to avoid the superior laryngeal nerve. 

 This nerve lies distinctly above the artery and is not liable to be injured if the thyroid 

 artery is followed out from its origin at the external carotid. Treves suggests ligat- 

 ing it between the sternomastoid and superior laryngeal branches, but it is more 

 readily reached closer to the external carotid artery. 



Ligation of the Lingual Artery. The lingual artery may be ligated for wounds, 

 as a preliminary step to excision of the tongue, and to check the growth of or bleed- 

 ing from malignant growths of the tongue, mouth, or lower jaw. 



The lingual 'artery springs from the external carotid opposite the hyoid bone 

 about i cm. above the bifurcation of the common carotid. It is composed of three 

 parts: the first, from its point of origin to the posterior edge of the hyoglossus 



