SPINAL ACCESSORY NERVE. 397 



distribution, we have striking evidence of its sensitive function. The 

 recurrent, or inferior laryngeal nerve, is the proper motor nerve, 

 and is distributed to the muscles of the larynx. 



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

 pneumogastric in the low r er part of the neck, and cross the lower 

 part of the common 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 con- 

 strictor muscle enters the larynx close to the articulation of the 

 inferior cornu of the thyroid with the cricoid cartilage. It is distri- 

 buted to all the muscles of the larynx, with the exception of the 

 crico-thyroid, and communicates 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 trachea, and com- 

 municates with the external laryngeal nerve and sympathetic. 



The Anterior pulmonary branches are distributed upon the ante- 

 rior aspect of the root of the lungs, forming, with branches from 

 the great cardiac plexus, the anterior pulmonary plexus. 



The Posterior pulmonary branches, more numerous than the ante- 

 rior, 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 accompanies it to the cardiac orifice of the stomach. 



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

 mogastric nerves ; they are spread out upon the anterior and poste- 

 rior surfaces of the stomach, and are likewise distributed to the 

 omentum, spleen, pancreas, liver, and gall-bladder, and communi- 

 cate, particularly the right nerve, with the solar plexus. 



The SPINAL ACCESSORY NERVE arises by several filaments from 

 the respiratory tract as low down as the fourth or fifth cervical 

 nerve, and ascends behind the ligamentum denticulatum, and between 

 the anterior and posterior roots of the spinal nerves, to the foramen 

 lacerum posterius. It communicates in its course with the posterior 

 root of the first cervical nerve, and soon becomes applied against 

 the ganglion of the pneumogastric and enclosed in the same canal 

 of dura mater. In the jugular fossa it divides into two branches; 

 the smaller joins the pneumogastric immediately below the superior 

 ganglion, and contributes to the formation of the pharyngeal nerve ; 

 while the larger or true continuation of the nerve passes backwards 

 behind the internal jugular vein, and descends obliquely to the upper 

 part of the sterno-mastoid muscle. It then pierces the sterno-mas- 

 toid and passes obliquely across the neck, communicating with the 



