1036 



THORAX. 



TABLE C. Thoracic Regions. 



REGION. 



Anterior .* 



Clavicular (subclavian of Laennec) - 

 Infra-clavian (anterior superior of Laennec) 

 Mammary --.-__ 

 Infra-mammary (sub-mammary of Laennec) 



Sternal superior, middle, inferior - 

 Lateral: 



Axillary - 



Infra-axillary (lateral of Laennec) 

 Inferior-lateral - 

 Acromial - 



Posterior : 



Scapular, upper and lower 



Interscapular ------ 



Infra-scapular (inferior dorsal of Laennec) 



SITUATION. 



Portion covered by the clavicle. 



Between the clavicle and 4th rib inclusive. 



Between the 4th and 8th ribs. 



From the 8th rib to the cartilaginous border 



. of false ribs. 



Over the respective parts of the sternum. 



All the axilla to the 4th rib inclusive. 



Between the 4th and 8th ribs at the side. 



Below the 8th to the false ribs inclusive. 



Between the clavicle, neck of humerus, and 

 along the upper margin of scapula, includ- 

 ing the root of the neck. 



Supra-spinous fossa and infra-spin ous fossa. 

 Between the inner margin of scapulae. 

 Below inferior angle of scapula and border of 

 serrati to the level of 12th vertebra. 



give the clearest sound upon percussion, and 

 the back the least clear. Below Harrison's 

 line, there is little or no evidence, from 

 percussion, of the presence of lung, except in 

 deep inspiration, and then the sound on per- 

 cussion is mixed with other sounds from the 

 abdominal organs. Only a small part of the 

 mammary region covers lung, scarcely any 

 being subjacent to the anterior parts of the 

 Cth, 7th, and 8th ribs. (See fig. 4, wherein 

 a transverse shading indicates the diaphragm. ) 



Internal conformation of the thorax. To 

 comprehend clearly the internal shape of the 

 thorax, it is necessary to take a cast of this 

 cavity. This may be done by making an open- 

 ing in the sternal region, just large enough to 

 admit the hand to remove the heart and 

 lungs, filling up the whole of the cavity with 

 plaster of Paris and returning the sternum, 

 then opening the abdomen, cutting away the 

 diaphragm, and so removing the cast, which 

 gives us a clear knowledge of the internal 

 conformation, and every kind of measurement 

 correctly. (Fig. 667. is a cast from the cavity 

 of figs. 680685, male subject.) We 

 have stated that the perfect thorax viewed 

 externally, and the same when the superficial 

 muscles and upper extremities are removed, 

 differ widely in their relative form. The tho- 

 racic cavity likewise differs remarkably from 

 either of these views. The general view is 

 that of a cone, but broader from side to side 

 than from before backwards : therefore the 

 cone is somewhat flattened. 



(a) Anterior region. This very closely re- 

 sembles the anterior region of the external 

 surface, being convex in its form, precisely 

 corresponding with the concave sternum. The 

 upper part, immediately behind the superior 

 end of the sternum, is rather concave (fig. 

 667 ). At this part the cavity divides into 

 two small cones, for the reception of the 



right and left apices of the lungs, which 

 ascend upwards to a variable height, 

 an inch or an inch and a half. Both apices 

 of the lungs are directed from below, upwards 



Fig. 667. 



Cast of the cavity of the thorax represented in figs. 

 1, 2, 3, 4, 5, and 6. 



and forwards; it is incorrect to consider 

 them as directed backwards ( fig. 667. , 

 which is the left apex seen above the 1st 

 rib.) In some cases, particularly where the 

 lung presents a puckered appearance, the 

 axis of the apex is inclined nearly to the 

 horizontal, and at all times it is about per- 

 pendicular to the sternum. These apices, 

 throughout advancing life, are tending to in- 

 cline forwards ; it is this portion above the 1 st 

 rib (fig. 667.), which is so vulnerable in phthisis 

 pulmonalis. There is great difference in the 

 precise character of these apices in different 

 individuals ; in fact we have seen no two the 

 same ; some are remarkably truncated, and 

 broad from before backwards ; others are thin 

 in this direction, and pointed ; some obtuse 

 and low, others acute and high. They have the 



