438 INFERIOR CERVICAL GANGLION. 



the carotid foramen in the petrous bone to opposite the lower border of 

 the third cervical vertebra. It is in relation in front with the sheath of the 

 internal carotid artery and internal jugular vein; and behind with the 

 rectus anticus major muscle. 



Its branches, like those of all the sympathetic ganglia in the trunk, are 

 divisible into superior, inferior,, external, and internal; to which may be 

 added, as proper to this ganglion, anterior. 



The superior (carotid nerve) is a single branch which ascends by 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 communications 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 com- 

 munication with the middle cervical ganglion. 



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

 those which communicate with the glosso-pharyngeal, pneumogastric, 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 laryngeal 

 nerve and its branches ; and the superior cardiac nerve, or nervus super- 

 ficialis cordis. 



The anterior branches accompany the carotid artery with its branches, 

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



flia; they are called, from the softness of their texture, nervi molles, and 

 om 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 branch, or branches, ascend to communicate with the supe- 

 rior 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 be- 

 hind it. 



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

 vical 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 ij of a semilunar 

 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 ganglion. 



The inferior branches pass some before and some behind the subclavian 

 artery, to join the first thoracic ganglion. 



The external branches consist of two sets ; one which communicates 

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



