PNEUMOGASTRIC NERVE. 475 



5. Filaments to the trachea, some of which penetrate the mem- 

 brane on its posterior part, others go between the cartilages; 

 they are then distributed to the lining membrane and to the 

 mucous glands of the part. 6. The inferior laryngeal nerve is 

 then distributed in branches to the inferior constrictor o the 

 pharynx and its lining membrane, but the most of its termi- 

 nating filaments penetrate to the larynx, between the thyroid 

 and the cricoid cartilage, and are lost upon the lining membrane 

 of the larynx, and upon the small muscles which move the ary- 

 tenoid cartilages. These terminating filaments anastomose 

 with such as come from the superior laryngeal nerve. 



It is generally stated by anatomists that the distribution of 

 the inferior laryngeal nerve to the larynx, is confined to the 

 thyreo-arytenoid, and posterior and lateral crico-arytenoid 

 muscles. Mr. G. Rainy states, in the London Medical Gazette, 

 that he has repeatedly traced its filaments, also, to the trans- 

 verse and oblique arytenoid.* The recurrent of the left side 

 forms a much larger loop than the other, and arises lower down, 

 inasmuch as it has to wind around the arch of the aorta, at the 

 origin of the left subclavian artery: with some inconsiderable 

 exceptions, its course and distribution afterwards are precisely 

 the same with those of the nerve of the right side. 



B. The Thoracic Branches of the pneumogastric are as fol- 

 low: The inferior tracheal nerves come from it just below the 

 recurrent: they are five or six in number; some of them go in 

 front of the trachea and bronchia, and others behind them. 

 They are complicated by anastomoses with the branches of the 

 recurrent nerve, and with those of the inferior cervical gan- 

 glion, and form a small plexus, denominated the anterior pul- 

 monary, which lies upon the front of the root of the lung, and 

 has its filaments following the branches of the pulmonary artery 

 through the lung. The posterior filaments supply the structure 

 of the bronchus by penetrating it, and some of them go to join 

 the posterior pulmonary plexus. 



As the pneumogastric gets behind the trachea and the bron- 

 chus, it is sensibly enlarged and somewhat flattened, the cohe- 

 sion of its fasciculi being somewhat looser. Several filaments 

 depart there from it, which form an intertexture with each 



* Am. Med. Journ. vol. iv. p. 



