630 THE SYMPATHETIC NERVES AND GANGLIA. 



(?/>) The filaments connected with the Gasserutn r/nnr/Hon of the fifth nerve 

 proceed sometimes from the carotid plexus, at others from the cavernous. 



(je) The deej) branch of the Vidian nerve passes backwards to the carotid plexus, 

 and after leaving the Vidian canal, lies in the cartilaginous substance which 

 closes the foramen lacerum medium. Valentin describes nerves as furnished to 

 the dura mater from the carotid plexus. 



Cavernous plexus.— The cavernous plexus, named from its position 

 in the sinus of the same name, is placed below and rather to the inner 

 side of the highest turn of the internal carotid artery. Besides giving 

 branches on the artery, it communicates with the third, the fourth, and 

 the ophthalmic division of the fifth cranial nerves. 



Branches. — {a) The filament which joins the third nerve comes into connec- 

 tion with it close to the point of division of that nerve. 



{]}) The branch to the fourth nerve, which may be derived from either the 

 cavernous or the carotid plexus, joins the nerve where it lies in the wall of the 

 cavernous sinus. 



i^c) The filaments connected with the opJithalmlc trunk of the .fifth nerve are 

 supplied to its inner surface. One of them is continued f oiT^'ards to the lenti- 

 cular ganglion, either in connection with or distinct from the nasal nerve. 



2. PHARYNGEAL NERVES AND PLEXUS. — Thcse nerves arise from the 

 inner part of the ganglion, and are directed obliquely inwards to the 

 side of the pharynx. Opposite the middle constrictor muscle they 

 unite with branches of the pneumogastric and glosso-pharyngeal 

 nerves ; and by their union with those nerves the pharyngeal plexus 

 is formed. Branches emanating from the plexus are distributed to the 

 muscles and mucous membrane of the pharynx. 



3. UPPER CARDIAC NERVE. — Each of the cervical ganglia of the 

 sympathetic furnishes a cardiac branch, the three being named respec- 

 tively the upper, middle, and lower cardiac nerves. 



These branches are continued singly, or in connection, to the large 

 prevertebral centre (cardiac plexus) of the thorax. Their size varies 

 considerably, and where one branch is smaller than common, another 

 will be founa to be increased in size, as if to compensate for the defect. 

 There are some differences in the disposition of the nerves of the right 

 and left sides. 



The upper cardiac nerve (n. cardiacus superficialis) of the right 

 side proceeds from two or more branches of the ganglion, with, in 

 some instances, an offset from the cord connecting the first two 

 ganglia. In its course down the neck the nerve lies behind the carotid 

 sheath, in contact with the longus colli muscle ; and it is placed in 

 front of the lower thyroid artery and the recurrent laryngeal nerve. 

 Entering the thorax, it passes in some cases before, in others behind 

 the subclavian artery, and is directed along the innominate artery to 

 the back part of the arch of the aorta, where it ends in the deep cardiac 

 plexus, a few small filaments continuing also to the front of the great 

 vessel. Some branches accompany the inferior thyroid artery to be dis- 

 tributed to the thyroid body. 



in its course dcmiwards this cardiac nerve is repeatedly connected with other 

 branches of the sjTiipathetic, and with the pneumo-gastric nerve. Thus about 

 the middle of the neck it is joined by some filaments from the external laryngeal 

 nerve; and, rather lower down, by one or more filaments from the trunk of the 

 pneumo-gastric neiTe ; lastly, on entering the chest, it joins with the rccui'rent 

 laryngeal. 



