CLINICAL SYNDROMES (STATUS THYMICUS, ETC.) 417 



dren, the diagnosis by palpation and percussion is easier ; but the confir- 

 mation by X-ray should be obtained whenever possible. 



For the X-ray technic, I cannot do better than quote Lange: "In 

 most cases a direct diagnosis can be made from a good rontgenogram. The 

 X-ray shadow of enlarged thymus is a wide median one. In some cases 

 the thymus shadow continues directly upward from the heart ; in others the 

 thymus shadow appears like a broad cap superimposed on the shadow of 

 the heart and great vessels. But a broadening of the median shadow 

 above the heart is not always due to an enlarged thymus. Benjamin and 

 Goett, in a careful study of the interpretation of the radiograms of the 

 chest in the infant, point out that a broadening of the shadow to the right 



Fig. 12. Normal shadows in the infant (Brayton & Heublein). 



may often be due to the superior vena cava. The appearance of the supe- 

 rior vena cava is, of course, familiar to every rontgenologist. The 

 younger the child, the more does the upper mediastinal shadow extend to 

 the right. When the veins are distended, as from crying or struggling, 

 this shadow may extend far to the right and may vary from time to time. 

 When, however, the upper mediastinal shadow extends well to the left, the 

 diagnosis of enlarged thymus is certain. False thymus shadows may be 

 produced by asymmetry of the position of the child when the exposure 

 is made. To avoid flopping of the heart and mediastinum to one or the 

 other side, thus giving false shadows, I have lately been placing the child 

 prone, and while an assistant or nurse holds the body and chest symmetri- 

 cally, an instantaneous exposure is made. In many cases, however, the 

 X-ray will fail to give conclusive evidence as to the presence of an en- 

 larged thymus. This is especially true when the enlargement is chiefly in 

 the anteroposterior diameter and very little in the lateral. Especially, 

 difficulty in demonstrating the thymus is encountered in very young 



