226 HEAD AND NECK 



Nervus Caroticus Interims. The internal carotid nerve 

 passes from the upper end of the ganglion into the carotid 

 canal. Its distribution will be considered later (p. 241). 



Nervi Carotid Externi. Two to six filaments, called 

 external carotid branches, run to the external carotid artery, 

 and form a loose interlacement around it called the external 

 carotid plexus from which a branch is given to the glomus 

 caroticum, 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 submaxillary 

 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 

 join the pharyngeal plexus and the superior laryngeal nerve. 



Nervus Cardiacus Superior. The superior cardiac nerve 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 con- 

 tinued 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, after crossing the left side of the 

 arch of the aorta, ends in the superficial cardiac plexus. 



Ganglion Cervicale Medium. The middle cervical 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 the ganglion 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, 

 it passes posterior or anterior to the subclavian artery ; on 



