THE ANTERIOR PART OF THE NECK 257 



the upper interspaces of the right side, and from the thoracic 

 visceral glands of the right side. About half an inch from 

 its termination it is sometimes joined by the right subclavian 

 and jugular lymph trunks, which convey lymph from the 

 right upper extremity and the right side of the head and 

 neck, respectively. Under these circumstances it constitutes 

 the main lymph drain for the following districts: (i) right 

 upper limb ; (2) right side of the head and neck ; (3) upper 

 part of right thoracic wall; (4) right side of diaphragm 

 and upper surface of liver; (5) thoracic viscera on right 

 side of median plane, viz. right side of heart and peri- 

 cardium and the right lung and pleura. But not uncommonly 

 the right jugular and subclavian lymph trunks open 

 separately into the internal jugular, the subclavian, or the 

 innominate vein. 



Cervical Pleura. The pleural sac of each side, with the 

 apex of the corresponding lung, projects upwards into the 

 root of the neck, and the dissector should now examine the 

 height to which it rises, and the connections which it estab- 

 lishes (see Figs, i and 5). Its height with reference to the 

 first pair of costal arches varies in different subjects. In 

 some cases it extends upwards for two inches above the 

 sternal end of the first rib ; in others for not more than one 

 inch. These differences depend on the degree of obliquity 

 of the thoracic inlet. Posteriorly, in the majority of cases, 

 the apex of the pleura corresponds in level with the neck 

 of the first rib. It forms a dome-like roof for each side of 

 the thoracic cavity, and is strengthened by a fascial expansion 

 (frequently termed Sib son' s fascia}, which covers it completely, 

 and is attached on the one hand to the transverse process 

 of the seventh cervical vertebra and on the other to the inner 

 margin of the first rib. 



Note that it is in relation with : (i) the scalenus anterior; 

 (2) the scalenus medius ; (3) the subclavian artery; (4) the 

 vertebral artery ; (5) the costo-cervical trunk ; (6) the superior 

 intercostal artery; (7) the internal mammary artery; (8) the 

 innominate vein ; (9) the vertebral vein; (10) the subclavian 

 vein; (i i) the vagus nerve ; (12) the phrenic nerve; (13) the 

 recurrent nerve on the right side; (14) the first thoracic 

 nerve; (15) the first thoracic ganglion of the sympathetic; 

 (16) the ansa subclavia (Vieusenii). 



The scalenus anterior covers the antero-lateral part of the 



VOL. II 17 



