THE NERVOUS SYSTEM. 



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cords there are three pairs of cervical ganglia, thirteen pairs 

 of thoracic ganglia, seven pairs of lumbar ganglia, and one 

 or two pairs of sacral ganglia, in addition to two median 

 unpaired sacral ganglia. 



In the cervical region the 

 sympathetic and vagus, or 

 tenth cranial nerve, are 

 bound in a common sheath 

 lying along the lateral aspect 

 of the carotid artery. One 

 or two centimeters craniad 

 of the first rib is the thyroid 

 or middle cervical ganglion, 

 whence the nerve proceeds 

 in two cords, enclosing the 

 subclavian artery, to the 



FIG. 107. CHIEF PART OF LEFT 

 HALF OF SYMPATHETIC SYSTEM 

 CRANIAD OF THE DIAPHRAGM. 

 Semidiagrammatic. 



5, 6, 7, 8, 9, and ip, Fifth, sixth, 

 seventh and eighth cervical 

 nerves, and first and second 

 thoracic spinal nerves; a, the 

 dorsal branch of the left vagus 

 In ; an, dorsal branch of the right 

 vagus ; ax, common dorsal vagus 

 formed by a and an ; avb, ventral 

 vagus ; be, cardiac branch of sg, 

 cr, carotid plexus; car, carotid 

 artery; cm, rami communi- 

 cantes; cp, cardiac plexus; dia, 

 diaphragm; g, ganglia in the 

 thoracic cavity ; ig, middle cer- 

 vical ganglion ; Ig, portion of 

 left lung; In, left vagus nerve; 

 nv, cranial nerve; pn, phrenic 

 nerve; pp, pulmonary plexus; 

 sn, sympathetic cord; sm, supe- 

 rior cervical ganglion; sb, left 

 subclavian artery; sg, stellate 

 ganglion or inferior cervical ; 

 spm, splanchnic major nerve; 

 vg> vagus ganglion; v, vagus 

 nerve. 



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