588 



THE VASCULAR SYSTEMS 



Rectus capitis anticus major muscles, the sympathetic cord being interposed between it and 

 the muscles. The recurrent laryngeal nerve and inferior thyroid artery cross behind the vessel 

 at its lower part. Internally, it is in relation \yith the trachea and thyroid gland, the latter 

 overlapping it, the inferior thyroid artery and recurrent laryngeal nerve being interposed; higher 

 up, with the larynx and pharynx. On its outer side are placed the internal jugular vein and 

 vagus nerve. At the lower part of the neck the internal jugular vein on the right side diverges 



FIG. 439. Plan of the 

 branches of the external 

 carotid. 



FIG. 438. Applied anatomy of the arteries of the neck, showing the carotid and subclavian arteries. 



from the artery, but on the leftside it approaches^, and often overlaps its lower part. Thi.s 

 is an important fact to bear in mind during the performance of any operation on the lower part 

 of the left common carotid artery. In this region the relation which the right and left recurrent 

 laryngeal nerves bear to the arteries is not identical. The left recurrent laryngeal nerve lies 

 behind the thoracic portion of the left common carotid artery and internal to the cervical portion 

 of the vessel. The right nerve passes obliquely upward and inward behind the right common 

 carotid to reach its inner side. 



i The hypoglossal nerve is not rightly placed in this drawing. It forms the upper side of a triangle, the two 

 lower sides of which are the two bellies of the Digastric. The lingual artery would then run under the Hyoglossus 

 muscle, below the hypoglossal nerve. (See Fig. 440.) 



