338 CLINICAL APPLIED ANATOMY. 



communicates below with the venous circle of the umbilicus, 

 above with the internal mammary vein, and receives tributaries 

 from the superficial network of the epigastrium. The blood 

 from all these superior veins is received below by the superficial 

 inferior epigastric veins, which accompany the superficial 

 epigastric artery, by perforating tributaries of the deep inferior 

 epigastric veins which accompany the deep epigastric artery, 

 and by branches of the lumbar veins. Thus the blood can find 

 its way from above into the internal saphenous veins, the 

 external iliac veins, and the inferior vena cava. 



The lateral group of superficial anastomosing veins is formed 

 as follows. On the side of the lower part of the thorax is a long 

 trunk known as the thoracico-epigastric vein. This communicates 

 above with the long thoracic (external mammary) vein, a tribu- 

 tary of the axillary vein. The long trunk communicates below, 

 usually in a plexiform manner, with the superficial inferior 

 epigastric vein, or with the superficial circumflex iliac vein, or 

 with both. On the side of the chest wall above, the costo-axillary 

 veins, which are lateral perforating vessels from the seven upper 

 intercostal spaces, unite and pass into the lateral main trunk, 

 whilst below the same trunk communicates with the superficial 

 lumbar veins. This long anastomosis links the axillary and 

 intercostal veins with the internal saphenous vein and the inferior 

 cava. The posterior group of anastomosing superficial veins 

 consists of large inter-communicating tributaries of the lumbar 

 and intercostal veins on the back. Engorgement of these veins 

 has been supposed to indicate obstruction of the azygos major 

 trunk. 



Pressure on the air tubes causes the most serious dyspnoea, 

 and also gives rise to various secondary changes in the lungs. 

 The dyspnoea may be paroxysmal, and then is probably due to 

 implication of nerves. The right vagus and the left recurrent 

 laryngeal nerves lie at the sides of the trachea, the vagi pass 

 behind the roots of the lungs, and the left recurrent laryngeal is 

 for a short distance in immediate relation with the thoracic part 

 of the trachea. The forward projection of the bodies of the 



