1038 



THORAX. 



large liver, are in activity and pushing up the 

 diaphragm. The superior opening or true apex 

 is greater from before backwards than trans- 

 versely, which is the very contrary to the 

 adult conformation. The inferior or true 

 base of the thorax is extremely wide in every 

 direction, from the encroachment of the ab- 

 dominal viscera. At birth the thorax sud- 

 denly enlarges, by the air expanding the lungs 

 to two or three times their previous cubic 

 dimensions. As age increases, the curvatures 

 of the ribs increase, and, with the vertebrae, 

 running up through the very centre of the tho- 

 rax, form the two great lateral grooves, peculiar 

 to man, for lodging the chief bulk of the lungs. 

 The depth of the thorax is diminished, while 

 its breadth is increased, and this participates 

 in that more perfect development of the 

 system at the age of puberty. It is at this 

 time that malformation of the chest fre- 

 quently becomes obvious, particularly in 

 females. In the adult age the thorax still 

 grows, but in a degree less apparent, until it 

 assumes the form of what is termed an 

 open chest, capable of expanding in any di- 

 rection, supplying us with air under violent 

 exercise, and resisting severe blows. As age 

 advances, through the decline of life, the 

 thorax has a tendency to collapse ; the bony 

 framework threatens to unite into one rigid 

 cage, the true apex droops forward, the shoul- 

 ders appear higher, and the round back of old 

 age becomes apparent, so that we may make a 

 tolerable guess at the age of an individual by 

 the conformation of the back. The erect 

 thorax is absolutely necessary to healthy 

 vigour, while the drooping-forward chest is 

 always accompanied with proportionate feeble- 

 ness. 



Sex. The chief difference of external 

 conformation between the sexes is due to the 

 largeness of the mammae, and the less width 

 across the shoulders in women than in men. 

 There is no distinguishing the sexes by the 

 internal form of the thorax, they so perfectly 

 resemble each other. The chest of the 

 female is only absolutely smaller, but not al- 

 ways that, certainly not relatively so. The 

 nipples are not uniformly in the same posi- 

 tion ; those of the female are generally closer 

 together than those of the male. 



^Conformation of the thorax affected ly 

 disease and occupation. The conformation 

 of the thorax chiefly depends upon the healthy 

 condition of the main pillar of support, the 

 spine ; but not always so, for that deformity 

 called " chicken breast" appears to be inde- 

 pendent of the condition of the spine. And, 

 again, emphysema of the lungs tends to pro- 

 trude the ribs and advance the sternum. 



Disease, as caries of the vertebrae, or an 

 atonic condition of the thoracic muscles, owing 

 to which the spinal column may yield, either 

 laterally, producing " lateral curvature," or an- 

 teriorly, giving " angular curvature," produces 

 the most marked distortion of this pillar of 

 support, and consequently of the whole thorax. 

 In youth, particularly in females, (from the pre- 

 sent system of education,) the spinal column, 



which is at all times sufficiently flexible, bends 

 under the weight of the head and arms ; and 

 for want of proper exercise the muscles of the 

 back become enfeebled, and unable to restore it 

 to the erect position. When " rickets" attack 

 the spine, it may curve in any direction, com- 

 pressing the ribs and projecting the sternum. 

 It is surprising to witness to what an extent 

 of deformity the thorax may attain, and yet 

 life still remain (see fig. 666., where costal 

 respiration conld not exist ; and where all 

 the abdominal viscera must have been 

 forced up into the cavity of the thorax, 

 for the 10th rib is nearly touching the 

 crista of the ilium). We have noticed a case 

 where such was the effort of nature to pre- 

 serve the thoracic and spinal cavities, that life 

 was maintained in a boy 14 years of age, 

 though 7 bodies of dorsal vertebrae were com- 

 pletely absorbed. 



In emphysema of the lungs, the sternum is 

 protruded, and the antero-poyterior diameter 

 of the thorax is increased sometimes by an 

 inch, the shoulders are raised, and the person 

 assumes always the form of a man who has 

 made the deepest inspiration. 



In phthisis pulmonalis, the thorax changes 

 its form, which is manifested by the shoulders 

 inclining forwards, the anterior and superior 

 parts bending in the same direction ; the 

 otherwise round full apex becomes flattened, 

 collapsing upon itself; and there is an in- 

 capacity to extend the apex ; this is a sure 

 and delicate test of that disease threatening, 

 before any symptoms can be detected by au- 

 scultation. In other stages there is a loss of 

 symmetry in the sides. In pleuritic effusion or 

 in empyema, one side may be full and immov- 

 able, whilst the other has to perform the 

 respiratory functions. In fact, disease of 

 the respiratory organs may produced change 

 in the form of the thorax, either downwards, 

 upwards, or outwards, or by collapse of the 

 apex. 



Frequently repeated or permanent compres- 

 sion, may produce many varieties of conforma- 

 tion of the thorax. Cruveilhier observes that 

 infants, in whom the thorax was perfectly well 

 formed at birth, have become deformed and 

 flattened on the sides of the thorax, by pres- 

 sure from the hands of the nurse. Slight ex- 

 ternal pressure in early life may be productive 

 of permanent deformity of the thorax, The 

 effect of strong and permanent constriction, as 

 from tight stays, occasions a distortion in 

 the form of the chest. This kind of com- 

 pression principally affects the lower part of 

 the thorax ; so that the 5th, 6th, 7th, 8th, 9th, 

 and 10th ribs are pressed forwards and in- 

 wards, because the length of their cartilages 

 allow them to yield readily : and the viscera 

 corresponding to these ribs, also undergo 

 alteration in their position and figure, en- 

 croaching upon the thoracic cavity, com- 

 pressing the lungs upwards, into the apices of 

 the chest. The imprudent custom of females 

 wearing a hard unyielding piece of wood, steel, 

 or whalebone up the front of their corset, 

 commonly produces a compression inwards of 



