THE NECK 141 



is usually separated by its companion vein, which runs down- 

 wards in front of it and crosses the subclavian artery to terminate 

 in the innominate vein. In order to avoid the inferior thyreoid 

 artery and the thoracic duct, the surgeon applies the ligature as 

 close as possible to the transverse process of the sixth cervical 

 vertebra, which forms the most important guide to the vertebral 

 artery. It may be necessary to tie the vertebral vein before 

 the artery is ligatured, and it may be impossible to avoid in- 

 cluding some fibres of the cervical sympathetic, which emerges 

 from the posterior wall of the carotid sheath in the lower part of 

 the neck. 



(d) In removal of the lower anterior group of the deep cervical 

 lymph glands good access is essential, and it is obtained by the 

 oblique (p. 135) or curvi-linear (p. 126) incision already described. 



The external jugular vein is exposed and a portion of it is 

 resected between ligatures. The fascial sheath of the sterno- 

 mastoid is opened, and the muscle is divided about an inch or 

 more above the clavicle, and the two cut ends are widely 

 retracted. This procedure exposes the carotid sheath medially 

 and, to its lateral side, the scalenus anterior, with the phrenic 

 nerve and the posterior belly of the omo-hyoid on its surface. 

 The ascending cervical artery, which supplies many of the glands 

 of this group, lies close to the medial side of the phrenic nerve. 

 In order to avoid injuring the phrenic nerve and, on the left side, 

 the thoracic duct, the glands are best removed by the finger 

 covered with gauze, but if the knife is used great care must be 

 exercised. In an old -standing case, where the glands have 

 become caseous, the scalenus anterior and even the sterno- 

 mastoid may be partially destroyed, and the phrenic nerve is 

 then more liable to injury. 



If the lower anterior group is the only group affected in the 

 neck, the enlargement is probably due to an ascending infection 

 from the bronchial lymph glands. As the disease spreads 

 upwards along the blood-vessels, the lymph glands which lie 

 along the lower part of the carotid sheath are the first to be 

 involved. Consequently these glands show a more advanced 

 stage of the disease than the glands lying along the lateral 

 border of the scalenus anterior, which will not present the same 

 number of caseous foci. On the other hand, in descending 

 infections, the higher glands of the group are the first to be 

 involved, and the lower glands always show a less advanced 

 stage of the disease. 



