Mediastina \ 5 3 



of the flaccid thoracic floor, push the viscera upwards, so that there is 

 an actual sinking in of the epigastric region. 



The abdominal viscera press the diaphragm upwards as one lies 

 in bed : therefore the bronchitic patient often breathes better when 

 propped in the sitting posture. 



Pleurodynia (TrAeupa, side ; oftwrj, pain) is pain in the chest-wall 

 which is not the result of pleurisy ; the chief merit of the term is in its 

 vagueness. Does it mean costal periostitis, muscular rheumatism, 

 intercostal neuralgia, or hepatitis ? Or is it the result of pressure upon 

 the posterior roots of some of the dorsal nerves of one side, or upon 

 nerves leaving the spine or entering the intercostal spaces ? For, after 

 all, pain is but a symptom of a disease, and sometimes a very mislead- 

 ing one. 



Pains between the shoulders are often conplained of in dys- 

 pepsia, that is whenever the stomach is out of working order. They are 

 probably caused by the association of filaments of the great splanch- 

 nic (o-rrXa-yxwi, viscera, p. 224) with the solar plexus below, and with 

 the higher dorsal nerves above, these latter nerves giving dorsal 

 branches to the skin in that region. Similarly the pains about the 

 right shoulder in liver disease were formerly explained, but a better 

 reason for their occurrence is given on p. 147. 



THE CAVITY OF THE THORAX 



The upper opening- of the thorax transmits the apex of each 

 lung, which extends for i^ in. into the roof of the neck. In the middle 

 line pass the sterno-hyoid and sterno-thyroid muscles, the inferior 

 thyroid veins (p. 155), remains of thymus, the trachea and oesophagus 

 with left recurrent laryngeal nerve, and also, on the left side, the 

 thoracic duct. 



A little removed from the middle line are the innominate artery, the 

 right vagus, and the left common carotid and subclavian arteries, with 

 the left vagus between them ; the two innominate veins ; the two 

 phrenic nerves ; cardiac filaments from sympathetic and from the 

 vagi ; the internal mammary and superior intercostal arteries descend- 

 ing into thorax ; part of the anterior division of the first dorsal nerve 

 mounting to the brachial plexus ; the longus colli and the cords of the 

 sympathetic. 



THE MEDIASTINA 



The mediastina are the spaces which ' stand in the middle ' (inedio, 

 std] of the chest, between the sternum and the spine, with the lung 

 and pleura on either side. The connective tissue which they contain 

 is liable to be the seat of suppuration. 



The anterior mediastinum is the space between the pleurae in 



