656 THE LYMPHATICS 



glands receive the lymphatics from the mammary gland, the side of the chest, and 

 the integument of the upper portion of the abdominal wall. The subscapular 

 glands receive the lymphatics from the integuments of the back. The infra- 

 clavicular glands receive the lymphatics from the outer part of the arm and integu- 

 ments covering the deltoid. They communicate, above with the cervical lymphatics, 

 and l)clo\v with the other glands in the axilla. The efferent vessels from all these 

 glands run upwards along the subclavian vein, and enter the neck either as four 

 distinct trunks, or as a single trunk (the axillary lymphatic trunk), and ter- 

 minate on the left side in the thoracic duct, and ou the right side in the right lym- 

 phatic duct. 



The communication between the glands in the axilla is very free. Thus, in 

 secondary infiltration following carcinoma of the breast, although the pectoral 

 glands may at first be alone affected, the remaining sets generally become also 

 involved. 



THE LYMPHATICS OF THE THORAX 



The lymphatics of the thorax may be divided into the parietal, which ramify 

 in the thoracic walls; and the visceral, which receive the lym})h from the thoracic 

 viscera. The thoracic duct, which conveys the lymph from the lower extremities 

 and from the greater part of the abdomen, passes through the posterior mediastinum 

 on its way to the confluence of the left internal jugular and subclavian veins at the 

 root of the neck, and is described here with the h-mphatics of the thorax. 



I. THE PARIETAL LYMPHATIC VESSELS AXD GLANDS OF 



THE Til OP AX 



1. The parietal lymphatic vessels are divided into the superficial and the 

 deep. 



The superficial parietal lymphatics ramify beneath the integuments, over 

 the pectoralis major in front, the serratus magnus laterally, and the trapezius and 

 latissimus dorsi behind. They all converge toAvards the axilla, and end in the 

 axillary glands. The lymphatics of the mammary gland end for the most part 

 in the pectoral set of the axillary glands, but those from the inner portion of the 

 gland pass through the second, third, and fourth intercostal spaces into the internal 

 mammary lymphatic chain of glands, and thus o]ien into the thoracic duct on the 

 left, and the right lymphatic duct on the right side. According to ^Nlacalister, the 

 lymphatics from the nipple and areola pass more deeply into the axilla, and end in 

 one of the axillary glands, placed nearer to the clavicle than the pectoral set. 



The deep parietal lymphatics are subdivided into (1) the intercostal and (2) 

 the diaphragiiiatie. 



(1) The intercostal lymphatics accompany the intercostal arteries and receive 

 the lymph from the intercostal muscles and the parietal pleura. Those in the 

 anterior part of the intercostal space run forwards and end in the internal 

 mammary or anterior intercostal lymphatic glands. Those in the posterior part of 

 the space run backwards, and — after receiving the dorsal lymphatic vessels which 

 accompany the dorsal branches of the intercostal arteries between the transverse 

 processes of the vertebrae, and return the lym})h from the muscles of the back and 

 from the spinal canal — end in tlie intercostal or jtosterior intercostal lymphatic 

 glands. 



(2) The diaphragmatic lymphatics follow the vessels of the diaphragm. 

 They terminate, anteriorly in tlie internal mammary and anterior mediastinal 

 lymphatic glands; postero-laterally in the lower intercostal lymphatics and in the 

 lymphatics accompanying the musculo-piirenic arter}-; and posteriorly in the pos- 



