134 The Bronchi 



in which the tube had been dashed right through the trachea and into 

 the oesophagus ! ' 



The right bronchus (see also p. 194), about an inch long, slopes 

 downwards and outwards in the root of the lung, to enter opposite the 

 fifth dorsal vertebra. As the right lung is larger than the left (which 

 has to make room for the heart), the right bronchus is the larger, and, 

 having a greater intake of air, is the more apt to receive a foreign body. 

 Because the right bronchus is larger than the left, the tracheal septum 

 must of necessity be rather to the left of the median line. 



The vena azygos major arches over the right bronchus in its course 

 to the superior cava. 



The left bronchus has to run across the front of the third part of 

 the arch of the aorta before it can divide in the root of its lung. It 

 is two inches long; its diameter is less than that of the right. It 

 enters the lung opposite the sixth dorsal vertebra, about an inch 

 lower than the right. It passes in the root of the lung beneath 

 the aortic arch, and in front of the oesophagus (p. 139), the third 

 part of the arch, and the left auricle. This last relationship is of 

 considerable clinical interest, for when, under the influence of mitral 

 regurgitation, that auricle is greatly dilated, it may obstruct the flow 

 of air along the left bronchus. (For the structure of the bronchi sec 



P- I95-) 



A foreign body in the bronchus may be extracted by appropriate 

 forceps through a free opening made low in the trachea. For this 

 purpose it will be well to stitch the edges of the tracheal ^vound to the 

 skin as soon as bleeding has been arrested, so that the 'way into the 

 bronchus may be made more direct and easy. If the foreign body 

 were taken down at the end of an inspiration, the area of lung to 

 which the bronchus led would be tideless but resonant, but after a 

 while oedema and, perchance, suppuration would render it solid. 



If attempts at extraction failed, the body might escape through 

 the tracheal wound, which should be stitched wide open ; or it might 

 escape through a localised thoracic abscess ; the pulmonary and costal 

 pleurae having become adherent, pneumothorax might not ensue. 



THE THYROID GLAND 



The thyroid gland consists of lateral lobes connected across the 

 second and third rings of the trachea by the isthmus. The outer sur- 

 face of the lateral lobes is convex ; their inner aspect is fitted on to the 

 side of the upper four or five rings of the trachea, the cricoid cartilage, 

 and the lower part of the thyroid cartilage. Often the isthmus extends 

 up to the level of the cricoid cartilage. 



A slender pyramidal lobe sometimes mounts from the isthmus to 

 the hyoid bone. Sometimes the isthmus is very wide and descends 

 almost to the sternum the tracheotomist should always endeavour to 

 operate above the isthmus. 



