366 



THE SYMPATHETIC NERVES. 



NF. 



THYR. 



with the middle cardiac and recurrent laryngeal nerves behind the subclavian 

 artery. 



On the left side, the lower cardiac often becomes blended with the middle cardiac 

 nerve, and the cord resulting from their union terminates in the deep cardiac 

 plexus. 



Branches to blood-vessels. From the lowest cervical and first dorsal ganglia 

 slender grey branches ascend along the vertebral artery in its canal, forming 

 a plexus (plexus vertebmlis) round the vessel by their intercommunications, and 

 supplying it with offsets. This plexus is connected with the cervical spinal nerves 

 as they cross the vertebral artery, and its ultimate ramifications are continued on 

 the intracranial branches of the vertebral and basilar arteries. 



"Fig. 233. THK SYMPATHETIC AT THK 



LOWER PART OF THK NECK. (Gr. D. T. ) 



A, B, middle cervical ganglion in two 

 pieces ; C, inferior cervical ganglion ; 

 D and E, first and second thoracic 

 ganglia. 



a, vertebral offset of inferior cervical 

 ganglion ; b, branch which ascends 

 through the foramen in the transverse 

 process of the last cervical vertebra to 

 join the seventh nerve. 



Below C are the origin of the inferior 

 cardiac nerve, and the termination of 

 the ansa subclavia. The arteries have 

 been drawn downwards and inwards in 

 order to display the nerves. The middle 

 cervical ganglion is, therefore, in a lower 

 position than natural ; and the com- 

 munication between the middle and lower 

 ganglia is directed more transversely 

 than would be the case if the parts Avere 

 in their natural place. 



Ansa subclavia ( Vieussenii}. 

 This name is given to a small 

 cord, often double, which passes 

 between the middle cervical and 

 the lower cervical, or first dorsal, 

 ganglia, in front of the sub- 

 clavian artery, forming a loop 

 around that vessel, and supplying it ^ith small offsets (plexus subclavms). From 

 the latter, filaments pass to the internal mammary artery, and in some cases 

 form a communication with the phrenic nerve. 



A direct twig of communication to the phrenic nerve is often given off from the inferior 

 cervical ganglion, less frequently from the middle cervical ganglion. 



The stellate ganglion of the dog and cat corresponds to the united lower cervical 

 and upper three or four thoracic ganglia of man. In the rabbit the name f/anf/llon stcU(ttnm 

 was used for the lower cervical ganglion, corresponding to the middle cervical ganglion 

 of man, by Ludwig and Thiry, whereas Cyon applied it to the first thoracic ganglion, which 

 corresponds to the lower cervical ganglion in man (Krause). 



CONSTITUTION OF THE CERVICAL SYMPATHETIC. 



The sets of fibres which have been recognized in the cervical sympathetic, and their 

 probable origin, are as follows : 



(a) Pupillo-dilator fibres, arising from the first, second, and third dorsal nerves. They 

 pass upwards in the ascending branch of the superior cervical ganglion, and thence to 

 the Gasserian ganglion, reaching the eyeball through the first division of the fifth and 

 the long ciliary nerves. (It is stated by many observers that pupillo-dilator fibres are 

 contained also in the seventh and eighth cervical nerves.) 



MID. 

 CARD. 



