CERVICAL GANGLIA CARDIAC NERVES. 431 



The anterior branches accompany the carotid artery with its 

 branches, around which they form intricate plexuses ; they are called, 

 from the softness of their texture, nervi molks. 



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 

 superior cervical ganglion. 



Its inferior branches descend to join the inferior cervical gan- 

 glion. 



Its external branches communicate with the third, fourth, and 

 fifth cervical nerves. 



Its internal branch is 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 arid some behind the sub- 

 clavian artery, to join the first thoracic ganglion. 



The external branches consist of two sets ; one which communi- 

 cates with the sixth, seventh, and eighth cervical nerves ; and one 

 which accompanies the vertebral artery along the vertebral canal, 

 forming the vertebral plexus. This plexus sends filaments to all the 

 branches given off by the artery, and communicates in the skull 

 with the filaments of the carotid plexus accompanying the branches 

 of the internal carotid artery. 



The internal branch is the inferior cardiac nerve, nervus cardi- 

 acus minor. 



CARDIAC NERVES.* The superior cardiac nerve (nervus super- 

 jicialis cordis) arises from the lower part of the superior cervical 

 ganglion; it then descends the neck behind the common carotid 

 artery, and, parallel with the trachea, crosses the inferior thyroid 

 artery, and accompanying the recurrent laryngeal nerve for a short 

 distance, passes behind the arteria innominata to the concavity of 

 the arch of the aorta, where it joins the cardiac ganglion. 



In its course it receives branches from the pneumogastric nerve, 

 and sends filaments to the thyroid gland and trachea. 



The Middle cardiac nerve (nervus cardiacus magnus) proceeds 

 from the middle cervical ganglion, or, in its absence, from the cord 



* There is no constancy with regard to the origin and course of these nerves ; there- 

 fore the student must not be disappointed in finding the description in discord with his 

 dissection. 





