318 HEAD AND NECK 



Nervus Caroticus Internus. This branch has been noted 

 passing from the upper end of the ganglion into the carotid 

 canal. Its distribution will be considered later. 



Nervi Carotid Externi. Two to six filaments, called 

 external carotid branches, run to the external carotid artery, 

 and form a loose interlacement around it and its branches. 

 From this external carotid plexus a branch is given to the 

 carotid body, and prolongations are continued on all the 

 branches of the artery. The part continued upon the external 

 maxillary artery supplies the sympathetic root to the sub- 

 maxillary ganglion, whilst the subdivision upon the middle 

 meningeal artery furnishes the corresponding root to the otic 

 ganglion, as well as the external superficial petrosal nerve which 

 runs to the ganglion geniculi of the facial nerve. 



Rami Laryngo-pharyngei. The laryngo-pharyngeal branches 

 pass between the two carotid arteries to join the pharyngeal 

 plexus, and some join the superior laryngeal nerve. 



Nervus Cardiacus Superior. This is a long slender branch 

 which springs by several roots from the ganglion, and then 

 proceeds downwards, posterior to the carotid artery. At 

 different stages of its course it is joined by other branches of 

 the sympathetic, by a branch from the vagus, and also by 

 filaments from the external laryngeal and recurrent nerves. 

 The right superior cardiac nerve is continued into the thorax 

 by passing posterior or anterior to the subclavian artery, and it 

 ends in the deep cardiac plexus. The left superior cardiac nerve 

 follows the left common carotid artery in the thorax, and, 

 crossing the left side of the arch of the aorta, ends in the 

 superficial cardiac plexus. 



Ganglion Cervicale Medium. This ganglion is the 

 smallest of the three ganglia of the neck. It . is placed 

 opposite the sixth cervical vertebra in close proximity to 

 the inferior thyreoid artery, upon which it not infrequently 

 rests. Its branches are: ( i ) grey rami communicantes, which 

 pass between the contiguous margins of the scalenus anterior 

 and longus colli muscles and connect it with the fifth and 

 sixth cervical nerves', (2) thyreoid branches, which run to the 

 thyreoid gland, along the inferior thyreoid artery, and form 

 connections with the external laryngeal and recurrent nerves ; 

 (3) the middle cardiac nerve. 



On both sides the middle cardiac nerve enters the thorax 

 and is lost in the deep cardiac plexus. On the right side 



