1034 A MANUAL OF ANATOMY 



mediastinum, in front of the pericardium. They receive their 

 afferent vessels from (i) the mesial portions of the right and left 

 lobes of the liver in the vicinity of the falciform ligament ; (2) the 

 adjacent portion of the diaphragm ; (3) the anterior part of the 

 pericardium ; and (4) the lower anterior intercostal or sternal 

 glands. Their efferent vessels pass to the thoracic duct and right 

 lymphatic duct. 



The posterior mediastinal glands are situated in the posterior 

 mediastinum, along the course of the descending aorta and oeso- 

 phagus. They receive their afferent vessels from the oesophagus, 

 the posterior part of the pericardium, and the vertebral portion 

 of the diaphragm. Their efferent vessels pass, for the most part, 

 to the thoracic duct. 



The bronchial glands are very numerous, and are situated partly 

 between the two bronchi, where these spring from the trachea, and 

 partly at the root of each lung. They are very dark in colour, 

 and receive their afferent vessels from the lungs and the visceral 

 pleurae. Their efferent vessels pass to the thoracic duct and right 

 lymphatic duct. 



The caval glands are situated in contact with the limited thoracic 

 portion of the inferior vena cava. They receive their afferent 

 vessels from the uncovered area of the posterior surface of the liver, 

 and also those deep lymphatics of that organ which accompany the 

 hepatic veins to the caval fossa. Their efferent vessels pass to the 

 thoracic duct. . 



Gangliated Cord of the Sympathetic. — ^The sympathetic system 

 in the thorax consists of (i) two gangliated cords, right and left, 

 and (2) a prevertebral plexus, namely, the cardiac plexus. The 

 latter plexus has been already described. The gangliated cord 

 lies on each side of the vertebral column behind the parietal pleura, 

 and superficial to the intercostal vessels. It presents, as a rule, 

 twelve ganglia, but the first is frequently united with the inferior 

 cervical ganglion, in which cases the number is reduced to eleven. 

 The upper ten ganglia are placed upon the heads of the correspond- 

 ing ribs, but the lower two lie upon the sides of the bodies of the 

 eleventh and twelfth thoracic vertebrae. The first thoracic ganglion 

 is the largest of the thoracic series, and is known as the ganglion 

 stellatum. The sympathetic cord leaves the thorax by passing behind 

 the inner part of the internal arcuate ligament of the diaphragm, 

 and so enters the abdomen. 



Branches — i. Of Communication. — ^These are called the rami 

 conimunic antes. Two of these, one white and the other grey, pass 

 between each ganglion and the adjacent intercostal nerve. The 

 white fibres are of spinal, and the grey of sympathetic, origin. 

 From the proximity of the ganglia to the intercostal nerves the 

 rami communicantes are characterized by their shortness, 



2. Of Distribution. — From the upper five ganglia small vascular 

 branches are given off, which are distributed to the coats of the 

 thoracic aorta. From the second, third, and fouith ganglia pid- 



