460 



ANATOMY IN A NUTSHELL. 



LESSON CXLV. 



The mediastinum is the -pace in the thorax which contains all the thoracic 

 viscera except the lungs. This word comes from two other words — medius, 

 the mil Idle, ami sto, I stand. The anterior mediastinum is the space between 

 the sternum anteriorly and the pericardium posteriorly. It contains the Tri- 

 angularis sterni muscle, parts of other muscles, lymphatic nodes, and areolar 

 tissue. The middle mediastinum is the space which is nearly the same as the 

 pericardiac cavity. It contains the heart, the ascending aorta, pulmonary 

 artery, and the superior vena cava, i.e., the parts of these which are within the 

 pericardium. It also has the phrenic nerves, the root of each lung, and lym- 

 phatic nodes. The posterior mediastinum is the space between the spine pos- 



PLATE CCXLVIII. 



EUSTACHIAN TUBE 

 PROC. COCHLEARIFORMIS. ' PROMONTORY. STAPES 



CAROTID CANAL/ 

 CANAL FOR FENESTRA ROTUNDA 

 -[■<-•— q TYMPANI. PYRAMID. 

 AQUEDUCTUS FALLOPII 



ANTRUM 



^\ V COCHLEARIFORMIS 

 l^^EUSTACHIAN TUBE 

 C\\ TYMPANUM. 

 CAROTID CANAL. 



%&Y ANTRUM. \ STYL0I0 PROCESS. 



MARROW AQUEDUCTUS FALLOPII. 

 CELLS. 



The Temporal Bone Laid Open. 



teriorly and the pericardium anteriorly. It contains the descending aorta, 

 the azygos v< ins the thoracic duct, the (esophagus, pneumogastric nerves, and 

 thi splanchnic aerves. The superior mediastinum is the space which has in 

 front the upper pari of the sternum and the spine behind. It is situated above 

 the pericardium and contains all the forty structures which pass through the 

 superior opening in the thorax except the apices of the lungs and the pleura'. 

 For structures which pass through the superior opening in the thorax see page232. 

 Name and classify these forty structures. 



LESSON CXLVI. 

 Muscles of the Superficial Abdominal Region. 

 Obliquus externus also called Descending oblique. — Description. — This 



