PXEUMOGASTRIC NERVE. 209 



The inferior, or recurrent laryngeal nerves present some 

 slight differences in their anatomy upon the two sides. Upon 

 the left side, the nerve is the larger, and is given off at the 

 arch of the aorta. Passing beneath this vessel, it ascends 

 in the groove between the trachea and the O3sophagus. In 

 its upward course, it gives off certain filaments which join 

 the cardiac branches, filaments to the muscular tissue and 

 mucous membrane of the upper part of the oesophagus, fila- 

 ments to the mucous membrane and the inter-cartilaginous 

 muscular tissue of the trachea, one or two filaments to the in- 

 ferior constrictor of the pharynx, and a branch which joins 

 the superior laryngeal. Its terminal branches penetrate the 

 larynx behind the posterior articulation of the thyroid with 

 the cricoid cartilage, and are distributed to all of the intrin- 

 sic muscles of the larynx, except the crico-thyroids, which 

 are supplied by the superior laryngeal. 



Upon the right side, the nerve winds from before back- 

 ward around the subclavian artery, and has essentially the 

 same course and distribution as upon the left side, except 

 that it is smaller and its filaments of distribution are not so 

 numerous. 



The important physiological point connected with the 

 anatomy of the recurrent laryngeals is that they animate all 

 of the intrinsic muscles of the larynx, except the crico-thy- 

 roid. Experiments have shown that these nerves contain 

 numerous filaments from the spinal accessory. 



The cervical cardiac branches, two or three in number, 

 arise from the pneumogastrics at different points of the cer- 

 vical portion and pass to the cardiac plexus, which is formed 

 in great part of filaments from the sympathetic. The tho- 

 racic cardiac branches are given off from the pneumogastrics 

 below the origin of the inferior laryngeals, and join the car- 

 diac plexus. 



The anterior pulmonary branches are few and delicate 

 as compared with the posterior branches. They are given 

 off below the origin of the thoracic cardiac branches, send 



