424 



SYMPATHETIC NERVE. 



carotid canal in the temporal bone, it com- 

 monly divides into two branches which pass 

 along the canal with the internal carotid 

 artery, the one being situated rather to the 

 inner, the other to the outer side of the 

 vessel ; they form numerous intercommunica- 

 tions with each other, giving rise to what is 

 termed the internal carotid plexus. 



(c) Pharyngeal Branches. These, from three 

 to six in number, leave the upper and inner 

 margin of the ganglion, pass inwards and 

 downwards, and unite with the pharyngeal 

 branches of the glossopharyngeal and vagus 

 nerves to form the pharyngeal plexus. 



(rf) External lateral Branches. These vary 

 in number ; sometimes there are only two 

 present ; at other times as many as six or 

 eight. They have a greyish-red colour, and 

 from the softness of their texture were termed 

 by Scarpa nervi molles, from their being 

 chiefly distributed to the blood vessels, they 

 were named by Scemmering vascular branches. 

 They arise from the front of the ganglion, and 

 pass downwards along the internal carotid 

 artery to the point of division of the common 

 carotid, where they give rise to the external 

 carotid plexus. Some filaments also unite 

 with the superior laryngeal nerve. 



(e) Superior or long cardiac Nerve, named 

 also the superficial cardiac branch, varies in 

 thickness, and is sometimes absent. It arises 

 from the anterior and lower portion of the 

 superior cervical ganglion, sometimes from 

 the intermediate cord between that and the 

 middle cervical ganglion, and sometimes it 

 derives filaments from both sources. It runs 

 downwards upon the longus colli muscle and 

 to the inner side of the sympathetic cord, and 

 passes behind or in front of the inferior 

 thyroid artery. In its course through the 

 neck it forms communications with the ex- 

 ternal laryngeal and descendens noni nerves ; 

 it also communicates with the vagus and re- 

 current laryngeal nerves, and sometimes with 

 the phrenic. Not unfrequently it is joined by 

 the cardiac branches, which leave the middle 

 and inferior cervical ganglion. It passes into 

 the chest in front of or behind the subclavian 

 artery, and along the arteria innominata, to 

 terminate in the cardiac plexus. The nerve 

 of the left side, after entering the chest, runs 

 along the left carotid artery to the arch of 

 the aorta, passing sometimes in front and 

 sometimes behind that vessel. 



(/) Communicating cord between the su- 

 perior and middle cervical Ganglia. The con- 

 necting cord between the superior and middle 

 cervical ganglia is commonly single, but occa- 

 sionally consists of two distinct portions. It 

 passes from the inferior extremity of the 

 superior cervical ganglion, which sometimes 

 seems to be prolonged downwards into it, 

 along the surface of the rectus capitis anticus 

 major muscle, behind the carotid artery, and 

 rather to the inner side of the pneumogastric 

 nerve, as far as the inferior thyroid artery. 

 Before sinking into the middle cervical gan- 

 glion it sometimes divides into two portions, 



one of which passes in front, the other behind 

 the vessel just mentioned. The communi- 

 cating branches with the third, fourth and 

 fifth cervical nerves frequently join it instead 

 of passing to the cervical ganglia. There is 

 also, according to L. F. Meckel, sometimes 

 formed upon it, above the inferior thyroid 

 artery, a small ganglion termed by some the 

 superior thyroid ganglion, and by others the 

 middle cervical ganglion. 



2. Middle cervical ganglion, smaller than 

 the superior ganglia of the same name, pre- 

 sents an irregularly oval or triangular shape, 

 and is situated on or near the inferior thyroid 

 artery. Communicating branches pass be- 

 tween it and the fifth and sixth cervical nerves; 

 it is also sometimes connected by filaments of 

 communication with the vagus and phrenic 

 nerves. From the inner side of the ganglion 

 several delicate greyish filaments pass off 

 which surround the inferior thyroid artery 

 forming a plexus, which is termed the inferior 

 thyroid plexus. These branches communicate 

 with the recurrent and internal laryngeal 

 nerves, as well as with the upper cardiac 

 nerve. The middle cervical ganglion also 

 gives a branch which is sent to the cardiac 

 plexus. This branch, termed the middle or 

 deep cardiac nerve, arises from the ganglion 

 by from two to four roots which unite into 

 a single or double stem. It passes into the 

 chest in front of the subclavian artery, but 

 sometimes behind that vessel, and runs along 

 the arteria innominata to the deep cardiac 

 plexus. On the left side it enters the chest be- 

 tween the left carotid and subclavian arteries. 



3. Inferior cervical ganglion, varies in its 

 size and form, which, in general, is more or 

 less semilunar ; its convexity being directed 

 downwards, its concave margin upwards. It 

 is situated between the transverse process of 

 the seventh cervical vertebra and the neck of 

 the first rib, behind the subclavian artery, and 

 behind and to the outer side of the root of 

 the vertebral artery. () Branches of com- 

 munication pass between the ganglion and 

 the seventh and eighth cervical nerves, as 

 well as the first intercostal nerve. It also 

 sometimes communicates with the phrenic 

 nerve and recurrent Jaryniiaeal. (b) From 

 the ganglion proceed several fine twigs, which 

 surround the subclavian artery as well as its 

 branches, forming small plexuses about them. 

 One of these accompanies the vertebral ar- 

 teries ; according to some it passes up along 

 with the artery into the cranium, subdividing 

 into as many secondary plexuses as there are 

 branches of the artery. Blandin states that 

 he has followed the branches of the nerve 

 along the basilar artery, upon the posterior 

 cerebral and cerebellar arteries. Whilst situ- 

 ated within the canal in the transverse pro- 

 cesses of the cervical vertebra it communi- 

 cates with several of the cervical nerves. 

 According to M. De Blainville several gan- 

 glia occur on this branch, equal in number to 

 the cervical vertebras, and hence he regards 

 the vertebral branch as the continuation up- 



