THE PLEURA 



1185 



and Intercostal muscles is the costal pleura (pleura costalis); that which covers 

 the convex surface of the Diaphragm is the diaphragmatic pleura (pleura diaphrag- 

 matica); that which rises in the neck, over the apex of the lung, is the cervical pleura 

 (cupula pleurae); and that which is applied to the adjacent structures of the 

 mediastinum is the mediastinal pleura (pleura mediastinalis). 



Reflections of the Pleurae (Fig. 897). Commencing at the sternum, the pleura 

 passes laterad, lines the costal cartilages, the inner surfaces of the ribs, and Internal 

 intercostal muscles, and at the back part of the thorax passes over the gangliated 

 cord of the sympathetic and its branches, and is reflected upon the sides of the 

 bodies of the vertebrae where it is separated by a narrow interval, the posterior 

 mediastinum (cavum mediastinale posterius), from the opposite pleura. From 

 the vertebral column the pleura passes to the side of the pericardium, which it 



COSTAPLEURAL 

 LIGAMENT 



FIG. 899. The supports of the pleural dome. The ossophagus, trachea, and arteries have been cut and pulled 

 aside to show the pleural reinforcements. (Poirier and Charpy.) 



covers to a slight extent; it then covers the back part of the root of the lung, from 

 the lower border of which a triangular sheet descends vertically by the side of 

 the posterior mediastinum to the Diaphragm, but is not attached thereto. This 

 sheet is the posterior layer of a wide fold, known as the broad ligament of the lung 

 (ligamentum pulmonale or liaamentum latum pulmonis). From the posterior 

 aspect of the lung root, the pleura may be traced over the convex surface of the 

 lung, the apex, and base, and also into the fissures between the lobes, on to its 

 inner surface and the front part of its root; it is continued from the lower margin 

 of the root as the anterior layer of the broad ligament, and from this it is reflected 

 on to the pericardium, and from it to the back of the sternum. Below, it covers 

 the upper surface of the Diaphragm, and extends, in front, as low as the costal 

 cartilage of the seventh rib; at the side of the thorax, to the lower border of the 

 tenth jrib_on jJie. leftjide and to the upper border of the same rib on tKe right side; 

 and behind, it reaches as low as the twelfth ribband sometimes even as low as 

 the transverse process of the first lumbar vertebra. Above, its apex projects, 

 through the superior aperture of the thorax into the neck, extending from one to 

 two inches above the anterior extremity of the first rib ; this portion of the sac is 

 strengthened by a dome-like expansion of fascia (Sibson's fascia) (Fig. 899), 

 attached in front to the inner border of the first rib, and behind to the anterior 



