THORAX. 



1039 



the sternum. We once noticed a case where 

 the sternum was forced inwards to such an ex- 

 tent, that the entire depth of the thorax, by 

 external measurement, from the middle of the 

 sternum to the corresponding part of the back, 

 only measured 2 inches instead of 8 or 9 

 inches ! 



Occupation likewise modifies the form 

 of -the thorax. The clerk who writes 

 many hours at the desk, carries himself dif- 

 ferently to the soldier. Coal-miners have 

 stooping chests when they work in districts 

 where the coal seam is thin, and the roof 

 consequently low, as in the north of Eng- 

 land. In fact, all trades or occupations 

 which require stooping for many hours to- 

 gether, tend to injure and malfonn the chest. 



Pigeon- or chicken-breast. This is a mal- 

 formation quite distinct from any of the 

 above mentioned, always affecting the sternal 

 region in particular. An explanation of this 

 curious disease has attracted the attention of 

 Mr. Shaw, to whom we are indebted for 

 the following remarks.* He noticed the 

 effects produced upon the thorax by violent 

 efforts of breathing in a child with croup. 

 If we watch, says Mr. Shaw, the motions 

 of the thorax in a young patient who is in 

 danger of suffocation from an obstruction in 

 the wind-pipe, we shall perceive that at each 

 inspiration, while the superior ribs and 

 sternum are raised and protruded as in com- 

 mon costal breathing, the lower ribs are, at 

 first, flattened, and then drawn inwards, so as 

 to produce a deep indentation on both sides. 

 The depression is greatest in the line of 

 junction of the ribs with their cartilages ; it 

 is as if a band had been tied tightly round 

 the waist, or resembles the indentation near 

 the margin of the chest, often seen in women 

 from tight lacing. The constriction lasts 

 during inspiration ; in expiration, the ribs by 

 their elasticity flap out and recover their 

 form. That the lower ribs should be drawn 

 inwards in the act of inspiration, diminishing 

 the area of the chest at a time when their 

 natural motion should enlarge it, will be un- 

 derstood b}' considering the relative conditions 

 of the thorax and the lungs in the laboured 

 respiration which arises from obstruction in 

 the wind-pipe. Under the sense of impend- 

 ing suffocation, the young patient instinctively 

 struggles to enlarge the cavity of the chest to 

 its greatest capacity ; but, while that effort is 

 making, the quantity of air that passes into the 

 lungs is very small, because of the obstruction 

 in the larynx or trachea : a portion of air 

 may reach the air-cells at the apex where the 

 bronchial tubes are short, but little or none 

 penetrates so far as the base of the lungs ; 

 consequently the lungs are imperfectly dilated. 

 If the child succeed in enlarging the area of 

 the chest in proportion to its powerful efforts, 

 \\hile the lungs were at the same time but 

 partially dilated, it would follow that a vacuum 

 would be produced in the space between the 



* Deformity of the Chest from Dyspnoea, Oct. 

 1841. Load. Med. Gaz. New Series, vol. i. 1842. 



parietes of the thorax and lungs. But owing 

 to the great flexibility of the ribs near the 

 lower margin of the thorax in childhood, the 

 atmospheric pressure overcomes the action 

 of the muscles, and thrusts in the sides so 

 as to preserve the balance of the air within 

 and that without : in common language, the 

 walls of the chest on each side are " sucked " 

 inwards, like the valve in a pair of bellows. 



When we look at the general shape of the 

 chest during the continuation of the con- 

 striction, we perceive at once a resemblance to 

 the pigeon-breast deformity ; there is in both 

 the same protrusion of the sternum, and the 

 same depression of the cartilages on each 

 side. 



The question therefore arises, can the de- 

 formity have a similar origin to the change in 

 the figure of the chest which is caused by 

 difficult respiration ? Dupuytren wrote a 

 memoir upon this form of distortion, and he 

 has shown that difficult respiration and pigeon- 

 breast deformity are frequently associated to- 

 gether, so that he has almost constantly found 

 that patients who are pigeon-breasted have at 

 the same time enlargement of the tonsils ; 

 but Dupuytren does not profess to explain 

 why the two complaints should go together. 

 Some years ago Mr. Shaw had under his 

 care a little boy with greatly enlarged tonsils, 

 which were very low down in the throat, 

 owing, as it appeared, to their having got 

 within the grasp of the constrictor muscles 

 of the pharynx. He had constant dyspnoea, 

 and occasional fits of suffocation, in one of 

 which Mr. Shaw performed laryngotomy: 

 on his admission into the hospital, and for 

 several weeks afterwards, it was observed that 

 he had the " pigeon-breast " form of chest ; 

 but after his tonsils were excised, and his 

 breathing had been perfectly free for some 

 time, the sternum subsided to its proper level, 

 and the thorax recovered its natural shape. 

 These facts prove that a connection, like 

 cause and effect, exists between obstruction 

 of the air passages and pigeon-breast de- 

 formity. It is not necessary that such impe- 

 diments should be so great as to produce 

 strongly marked symptoms of dyspnoea ; for, 

 while the distortion is being produced the 

 child is growing, both the size and shape 

 of the chest are undergoing a natural change. 

 Mr. Shaw justly considers it quite possible 

 that a cause which may have very slight in- 

 fluence in changing the figure of the thorax, if 

 operating only for a week or a month, will, if 

 continued longer, disturb and modify the pro- 

 cess of growth ; so that after intervals of half- 

 years or years, a decided effect will be exhibited 

 in the form of the chest. It is not impossible 

 that continued disease in the air passages of 

 children, which may fail to attract much at- 

 tention, or at least may not be thought capa- 

 ble of producing distortion, may nevertheless 

 gradually and insidiously give rise to the per- 

 manent deformity of "pigeon-breast." Mr. 

 Shaw particularly refers to enlargement of 

 the tonsils, attended even with slight incon- 

 venience ; to enlargement of the lymphatic 



