THE MEDIASTINA 201 



Costo-colic ligament (vide p. 191.) 



The foramen of Winslow is the orifice behind the right free 

 margin of the small omentum, by which the smaller peritoneal 

 sac communicates with the general peritoneal cavity. 



Relations : 



In Front. 



Hepatic artery. 

 Portal vt-.in. 

 Common bile-duct. 



THE MEDIASTINA. 



The superior mediastinum is the space above the peri- 

 cardium extending upwards to the root of the neck. 



Boundaries : 



Above. Superior aperture of the thorax. 



Below. Plane passing from lower part of body of 4th dorsal 

 vertebra, to the junction of the gladiolus and manubrium of 

 sternum. 



In front. Manubrium and origins of sterno-hyoid and sterno- 

 thyroid muscles. 



Behind. First four dorsal vertebrae, and lower ends of longi 



coin. 



Laterally. The parietal or mediastinal pleura, passing back 

 from posterior surface of sternum to vertebrae. 



Contents. Trachea (lower end), oesophagus, thoracic duct, 

 transverse part of arch of aorta, innominate artery, thoracic 

 part of left carotid and subclavian arteries, innominate veins, 

 upper part of superior vena cava, phrenic and pneumogastnc 

 nerves, left recurrent laryngeal and the cardiac nerves, 

 lymphatic glands and remains of thymus gland. 



The anterior mediastinum is the space between the two 

 pleurae in front of the pericardium ; it is narrow above, but 

 broader below. 



Boundaries : 



In front. Sternum, with 5th, 6th, and part of yth left costal 

 cartilages, triangularis sterni, and left internal mammary 

 vessels. 



Behind Pericardium. 



T..iterallv Pleura 



