INFERIOR LARYNGEAL NERVE. 407 



it communicates with the recurrent laryngeal nerve. Behind the internal 

 carotid it gives off the external laryngeal branch, which sends a twig to the 

 pharyngeal plexus, and then descends to supply the inferior constrictor 

 and crico-thyroid muscles and thyroid gland. This branch communicates 

 inferiorly with the recurrent laryngeal and sympathetic nerve. 



Mr. Hilton of Guy's Hospital, concludes from his dissections* that the 

 superior laryngeal nerve is the nerve of sensation to the larynx, being dis- 

 tributed solely (with the exception of its external laryngeal branch and a 

 twig to the arytenoideus) to the mucous membrane. If this fact be taken 

 in connexion with the observations of Sir Astley Cooper, and the dissec- 

 tions of the origin of the nerve by Mr. Edward Cock, we shall have ample 

 evidence, both in the ganglionic origin of the nerve and in its distribution, 

 of its sensitive function. The recurrent, or inferior laryngeal nerve, is the 

 proper motor nerve of the larynx, and is distributed to its muscles. 



The Cardiac branches, two or three in number, arise from the pneumo- 

 gastric in the lower part of the neck, and cross the lower part of the com- 

 mon carotid, to communicate with the cardiac branches of the sympathetic, 

 and with the great cardiac plexus. 



The Recurrent laryngeal^ or inferior laryngeal nerve, curves around the 

 subclavian artery on the right, and the arch of the aorta on the left side. 

 It ascends in the groove between the trachea and oesophagus, and piercing 

 the lower fibres of the inferior constrictor muscle enters the larynx close 

 to the articulation of the inferior cornu of the thyroid with the cricoid car- 

 tilage. It is distributed to all the muscles of the larynx with the excep- 

 tion of the crico-thyroid, and communicates on the arytenoideus muscle 

 with the superior laryngeal nerve. As it curves around the subclavian 

 artery and aorta it gives branches to the heart and root of the lungs ; and 

 as it ascends the neck it distributes filaments to the oesophagus and tra- 

 chea, and communicates with the external laryngeal nerve and sympa- 

 thetic. 



The Anterior pulmonary branches are distributed upon the anterior as- 

 pect of the root of the lungs, forming, with branches from the great car- 

 diac plexus, the anterior pulmonary plexus. 



The Posterior pulmonary branches, more numerous than the anterior, 

 are distributed upon the posterior aspect of the root of the lungs, and are 

 joined by branches from the great cardiac plexus, forming the posterior 

 pulmonary plexus. 



Upon the oesophagus the two nerves divide into numerous branches, 

 which communicate with each other and constitute the cesophageal plexus 

 which completely surrounds the cylinder of the oesophagus, and accompa- 

 nies it to the cardiac orifice of the stomach. 



The Gastric branches are the terminal filaments of the two pneumogas- 

 tric nerves ; they are spread out upon the anterior and posterior surfaces 

 of the stomach, and are likewise distributed to the omentum, spleen, pan- 

 creas, liver, and gall-bladder, and communicate, particularly the right 

 nerve, with the solar plexus. 



glion. 12. Its trunk. 13. Its pharyngeal branch forming the pharyngeal plexus (14), 

 assisted by a branch from the glosso-pharyngeal (8), and one from the superior laryn 

 geal nerve (15). 16. Cardiac branches. 17. Recurrent laryngeal branch. 18. Anterior 

 pulmonary branches. 19. PC sterior pulmonary branches. 20. (Esophageal plexus. 21. 

 Gastric branches. 22. Origin of the spinal accessory nerve. 23. Its branches distri 

 buted to the sterno-mastoid muscle. 24. Its branches to the trapezius muscle. 

 * Guy's Hospital Reports, vol. ii. 



