486 CERVICAL GANGLIA. 



the side of the internal carotid, and divides into two branches ; one 

 lying to the outer side, the other to the inner side of that vessel. 

 The two branches enter the carotid canal, and by their communica- 

 tions with -each other and with the petrosal branch of the Vidian, 

 constitute the carotid plexus. 



The inferior or descending branch, sometimes two, is the cord of 

 communication with the middle cervical ganglion. 



The external branches are numerous, and may be divided into two 

 sets : those which communicate with the glosso-pharyngeal, pneu- 

 mogastric, and hypoglossal nerves ; and those which communicate with 

 the three first cervical nerves. 



The internal branches are three in number : pharyngeal, to assist in 

 forming the pharyngeal plexus ; laryngeal, to join the superior laryn- 

 geal nerve and its branches ; and the superior cardiac nerve, or nervus 

 superficialis cordis. 



The anterior branches accompany the carotid artery with its branches, 

 around which they form intricate plexuses, and here and there small 

 ganglia ; they are called, from the softness of their texture, nervi 

 molles, and from their reddish hue, nervi subrufi. 



The Middle cervical ganglion (thyroid ganglion) is of small size, 

 and sometimes altogether wanting. It is situated opposite the fifth 

 cervical vertebra, and rests upon the inferior thyroid artery. This 

 relation is so constant, as to have induced Haller to name it the 

 " thyroid ganglion." 



Its superior brunch, or branches, ascend to communicate with the 

 superior cervical ganglion. 



Its inferior branches descend to join the inferior cervical ganglion ; 

 one .of these frequently passes in front of the subclavian artery, the 

 other behind it. 



Its external branches communicate with the third, fourth, and fifth 

 cervical nerves. 



Its internal branches are, filaments which accompany the inferior 

 thyroid artery, the inferior thyroid plexus ; and the middle cardiac 

 nerve, nervus cardiacus magnus. 



The Inferior cervical ganglion (vertebral ganglion) is much larger 

 than the preceding, and is constant in its existence. It is of a semi- 

 lunar form, and is situated upon the base of the transverse process of 

 the seventh cervical vertebra, immediately behind the vertebral artery : 

 hence its title to the designation " vertebral ganglion." 



Its superior branches communicate with the middle cervical gan- 

 glion. 



The inferior branches pass some before and some behind the sub- 

 clavian artery, to join the first thoracic ganglion. 



The external brandies consist of two sets ; one which communicatts 

 Avith the sixth, seventh, and eighth cervical and first dorsal nerve ; 

 and one which accompanies the vertebral artery along the vertebral 



