THE PNEUMO-GASTRIC NERVE. 



263 



again into a single trunk, which, descending through the diaphragm along the back 

 of the oesophagus, is finally divided between the posterior surface of the stomach and 

 the solar plexus. 



On the left side the pneumo-gastric nerve, entering the thorax between the left 

 carotid and subclavian arteries and behind the left innominate vein, crosses over the 



Fig. 179. THE DISTRIBUTION AND CONNECTIONS OF THE PNEUMO-GASTRIC NERVE ON THE LEFT SIDE IN THE 

 NECK AND UPPER PART OF THE THORAX. (From Sappey, after Hirschfeld and Leveille".) 



1, pneumo-gastric nerve ; 2, ganglion of its trunk ; 3, accessory part of the spinal accessory ; 4, union 

 of the pneumo-gastric with the hypoglossal ; 5, pharyngeal branch of the pneumo-gastric ; 6, superior 

 laryngeal nerve ; 7, external laryngeal ; 8, communication of the external laryngeal nerve with the 

 superior cardiac branch of the sympathetic ; 9, inferior or recurrent laryngeal ; 10, superior, and 11, 

 inferior cervical cardiac branches ; 12, 13, posterior pulmonary plexus ; 11, lingual branch of the inferior 

 maxillary nerve ; 15, distal part of the hypoglossal nerve ; 16, glosso-pharyngeal nerve ; 17, spinal acces- 

 sory nerve, uniting by its inner branch with the pneumo-gastric, and by its outer passing into the sterno- 

 mastoid muscle ; 18, second cervical nerve ; 19, third ; 20, fourth; 21, origin of the phrenic nerve ; 

 22, 23, fifth, sixth, seventh, and eighth cervical nerves, forming with the first dorsal the brachial 

 plexus ; 24, superior cervical ganglion of the sympathetic ; 25, middle cervical ganglion ; 26, inferior 

 cervical ganglion united with the first dorsal ganglion ; 27, 28, 29, 30, second, third, fourth, and fifth 

 dorsal ganglia. 



arch of the aorta, below which its recurrent laryngeal branch turns inwards and up- 

 wards. It then passes behind the root of the left lung, forming, like its fellow, a 



