634 



DISSECTION OF DEEP VESSELS AND NERVES OF NECK. 



sympa- 

 thetic, 

 and spinal 

 nerves. 



Branches of 

 supply. 



To pharynx 



through 



pharyngeal 



plexus. 



Upper 

 branch to 

 larynx : 



its external 



offset. 



Branches to 

 the heart, 

 upper and 

 lower. 



Lower 

 branch to 

 larynx 



gives 

 branches 

 to heart, 



between it and the hypoglossal nerve. Other branches connect it t 

 the upper ganglion of the sympathetic and the loop of the first 

 cervical nerves. 



Branches for distribution. The cervical branches arise from th 

 lower ganglion and the trunk of the nerve, and are directed inward* 

 to supply the pharynx, the larynx, and the heart. 



a. The pharyngeal branch (fig. 225, 5 ) springs from the uppe 

 part of the ganglion of the trunk, and is directed inwards over th 

 internal carotid artery to the side of the pharynx, being joined i) 

 its course by the descending pharyngeal branches of the glosso 

 pharyngeal nerve. OR the surface of the middle constrictor, th' 

 ramifications of the united nerves communicate freely together and 

 with the pharyngeal branches of the sympathetic, form tin 

 pharyngeal plexus. The offsets of the plexus enter the wall of thi 

 pharynx and supply the constrictor muscles, the palato-glossus 

 palato-pharyngeus, levator palati and azygos uvulne muscles, anc 

 the mucous membrane between the mouth and the larynx. 



b. The superior laryngeal nerve (fig. 225, f> ) is much larger thai 

 the preceding branch, and comes from the middle of the ganglion o 

 the trunk. It runs obliquely downwards and forwards, passing or 

 the inner side of the internal and external carotids, to the interva 

 between the hyoid bone and the thyroid cartilage. Here it perforates 

 the thyro-hyoid membrane, and divides into branches for the supply 

 of the mucous membrane of the larynx (page 697). Whilt 

 beneath the internal carotid artery it furnishes the following 

 offset : 



The external laryngeal branch (fig. 225, 7 ) descends on the inferior 

 constrictor muscle to the side of the larynx, and then beneath the 

 sterno-thyroid to the crico-thyroid muscle in which it ends. Near 

 its origin it gives off a filament to join the upper cardiac branch of 

 the sympathetic ; and lower down it supplies twigs to the inferior 

 constrictor muscle. 



c. Cardiac branches. One or two small cardiac nerves spring from 

 the pneumo-gastric at the upper part of the neck, and join cardiac 

 branches of the sympathetic. At the lower part of the neck, on each 

 side, there is a large cardiac nerve which descends into the thorax : 

 the right one joins the deep nerves to the heart from the sympathetic 

 and the left terminates in the superficial cardiac plexus. 



d. The inferior or recurrent laryngeal nerve leaves the pneumo- 

 gastric trunk on the right side opposite the subclavian artery, and 

 winding round that vessel, takes an upward course in the neck to the 

 larynx, ascending beneath the common carotid artery, along the 

 groove between the trachea and the oesophagus, and crossing either 

 in front of or behind the inferior thyroid artery. At the larynx it 

 enters beneath the ala of the thyroid cartilage, where it will be 

 afterwards traced (page 697). The following branches arise from it : 



Some cardiac branches leave the nerve as it turns round the sub- 

 clavian artery ; these enter the thorax, and join the cardiac nerves 

 of the sympathetic. 



