410 



GEOEGE H. HOXIE 



(d'Espine's sign), points to the mediastinal or bronchial lymph glands as 

 the source of the dullness. (2) The broadening of the aorta (dilatation) 

 usually betrays itself by a band of dullness from the lower manubrium 



down through the sternum. 

 (3) Thrill and pulsation 

 also point to a vascular ori- 

 gin. (4) The submanubrial 

 dullness should persist in 

 both the horizontal and ver- 

 tical postures, because the 

 aortic arch may be mobile 

 enough to give different per- 

 cussion notes in the differ- 

 ent postures. 



If none of these differ- 

 ential signs is present, one 

 should then proceed to use 

 the fluoroscope. The patient 

 should be viewed first in the 

 antero-posterior position. If 

 the presence of an increased 

 shadow be verified, then it 

 should be examined for 

 movement when the patient 

 swallows (thyroid), and for 

 pulsation (aorta or aneur- 

 ism). Now, by turning the 

 patient and viewing the 

 chest in the right oblique 

 (50 degrees) position of Va- 

 quez and Bordet, one can 

 determine if the shadow fills 

 the clear space between the 

 spine and the vessels. In 

 this case the shadow is due 

 to lymph glands and not the 

 thymus. 



The accompanying cut 



(Fig. 10) shows a skiagram taken in the right oblique position, 

 showing the thymic shadow in the retromanubrial space, in an 

 adult. 



Another check is to note if the trachea has been pushed aside by the 

 thymic mass, as in Fig. 11. 



For the determination of the presence of an enlarged thymus in chil- 



Fio-. 11. Deviation of the trachea in thymic hy- 

 perplasia. 



