DISSECTION OF THE THORAX 



407 



Look for them in the sinus phrenicocostalis and at the 

 junction of the pleura mediastinalis with the pleura dia- 

 phragmatica. 

 (g) Differences between lines of pleural reflection on right and left sides. 



Removal of Central Portion of Sternum. 



Carefully remove the portion of the sternum between the 

 superior and inferior transverse cuts, with costal cartilages at- 

 tached, but save the piece for the study of the sternocostal articu- 

 lations later. Separate the pleura pericardiaca (of the pleura 

 mediastinalis) from the side of the pericardium. The following 

 structures become visible : 



(a) Phrenic nerve (N. phrenicus). 



(b) Branches of A. mammaria interna. 



(ba) Pericardiacophrenic artery (A. pericardiacophrenica) (0. T. 



arteria comes nervi phrenici). 



(bb) Anterior mediastinal arteries (Aa. mediastinales anteriores). 

 (be) Thymic arteries (Aa. thymicae). 



(bd) Bronchial rami (rami bronchioles}. 



FIG. 203. 



The lungs seen from in front, s, lobus superior ; m, lobus medius ; i, lobus inferior. (From 

 Gegenbaur, Lerhb. der Anat. des Mensch., Leipzig, 1899, 7 Aufl., Bd. ii. p. Ill, Fig. 432.) 



Lungs (Pulmones). (Figs. 202 and 203.) 



The right lung (pulmo dexter] and the left lung (pulmo sin- 

 ister) may next be studied. With the consent of the dissector of 

 the head and neck inflate the lungs with air. Do this by inserting 

 the nozzle of the bellows in the cervical portion of the trachea. 

 After inflation ligate the trachea. Now study the external form 

 of each lung, comparing the findings in the cadaver with atlas 

 illustrations, text-book descriptions, and the His-Steger models. 

 In each lung study the following: 



