396 HEALTH AND DISEASE 



of the trachea, and assists in forming the bronchial plexus. It now gives 

 off tlie oesophageal nerve, which goes to the stomach and the solar plexus. 

 In its course the pneumogastric nerve gives branches — 



(1) To the superior cervical ganglion of the sympathetic. 



(2) The pharyngeal branch unites with a branch of the ninth pair 

 given off near the termination of the common carotid, and these, together 

 with a branch of the sympathetic, form the pharyngeal plexus, which 

 distributes fibres to the pharynx and commencement of the oesophagus. 



(3) The superior laryngeal nerve enters an opening beneath the 

 appendix of the superior border of the thyroid cartilage, and supplies the 

 mucous membrane of the larynx with sensibility. It also gives branches 

 to the mucous membrane of the root of the tongue, the pharynx, and 

 oesophagus, likewise to the crico-thyroid, and crico-pharyngeus muscles. 



The inferior laryngeal differs not only in its point of origin, but likewise 

 in the course it su])sequently takes. 



The right inferior laryngeal or recurrent nerve arises from 



the parent trunk near to the dorso-cervical artery at the entrance to the 

 chest. It passes round the root of this vessel and escapes from the 

 chest between the carotid artery and the trachea, to which and the 

 oesophagus it gives filaments. It then passes up the neck in company 

 with the former as high as the larynx, and gives its fibres to the pos- 

 terior crico-arytenoideus, the lateral crico-arytenoideus, the arytenoideus, 

 and the thyro-arytenoideus muscle. Before leaving the chest this nerve 

 gives branches to the cardiac plexus, and communicates with the middle 

 cervical ganglion of the sympathetic. 



(4) The left inferior laryngeal or recurrent nerve is given off 



from the pneumogastric ojjposite the root of the aorta; it then courses 

 its way round that vessel, as did the right round the cervico-dorsal artery. 

 Passing out of the chest between the two first ribs, it follows the carotid 

 artery up the neck to reach the larynx. Here it distributes its branches 

 to the posterior and lateral crico-arytenoideus, the arytenoideus, and the 

 thyro-arytenoideus muscles. 



It is longer than the right nerve, having to pass round the aorta, and 

 when paralysed gives rise to the disease known as " roaring and whistling". 



A branch of the pneumogastric amalgamates with the middle or inferior 

 cervical ganglion of the sympathetic, and a pulmonary plexus is formed at 

 the bifurcation of the trachea; branches from it follow the divisions of the 

 bronchi along their lamifications, and others enter into the cardiac plexus. 



Eleventh, Spinal Accessory. — This nerve arises from the whole 

 cervical spinal cord, and passes up the neck between the superior and the 

 inferior roots of the cervical spinal nerves. In its course along the neck 



