426 SPECIAL ANATOMY. 



glion on the art. thyreoid inf., receiving ramuli from the fifth and 

 sixth, or fifth to the seventh cervical nerves, and the principal fila- 

 ments of plex. thyreoideus inferior (is not to be confounded with 

 the ganglionic enlargement before the fourth and fifth cervical ver- 

 tebrae ; this is often wanting). Between it and the inferior cervi- 

 cal we find, almost always, small ganglia interposed. 



a. Plexus thyreoideus inferior, passes from the cervical portion, 

 form plexuses around the art. thyr. inf., gives branches to the 

 thyroid gland, and receives those of: the plexus of the cardiac 

 nerves in the inferior part of the neck, from n. recufrens,and. 

 the trunk of the vagus. In it lies before or behind art. thyreoid. 

 infer, a gangl. thyreoideum inferius. 



b. N. cardiacus medius, arises from or below the gangl. c. me- 

 dium, passes downwards and inwards behind the carotis, form 

 plexus around this (forming in the thorax the gangl. cardiac, 

 medium), and enter along it the posterior cardiac plexus ; it 

 unites with : plex. thyreoid. infer., with branches from gangl. 

 infimum c. and n. vagus. 



674. 3. Ganglion cervicale infimum s. stellatum, flat, round- 

 ish, or three to four cornered, rarely double, sometimes blended 

 with the first thoracic ganglion, lying before the root of proc. 

 transv. of the seventh cervical vert., or on the neck of the first rib, 

 higher or lower upon the art. vertebral, behind art. subclavia. Its 

 roots come from the sixth and seventh, also from fourth, fifth, and 

 eighth cervical nerves. Its branches are : 



a. N. cardiacus inftmus, half a line thick, passes downwards 

 and inwards, with the trunk of the vagus, and then on the 

 arcus aortce to the inferior cardiac plexus ; is sometimes want- 

 ing upon the right side, forms united with n. card, medius, 

 the thick (crassus) cardiac nerves. Connexions : with plex. 

 vertebral., subclav., laryng. infer, and vagus. 



b. Branches (three) for art. vertebralis, ascending on this in the 

 canal, vertebral., surrounding it like a plexus, and anasto- 

 mosing with the cervical nerves. 



c. Branches (two) for art. subclavia, forming loops about it, and 

 sinking into the first thoracic ganglion. 



d. The trunk of n. sympath., between the lowest cervical and 

 first thoracic ganglion, divides and descends before and behind 

 art. subclavia. 



675. II. Pars thoracica n. sympathici. 



The thoracic portion descends along the vertebral column (from 



