448 mi. C. F. SOXNTAG ON THE 



The thoracic cords hiive fewer gangliii than tlie numbers of 

 intercostal nerves, and the rami communicantes are of consider- 

 al)le lengtli. In text-fig. 20 B aie sliown the slender wJiite i-amus 

 communicans (w.r.c) emerging from tlie vert('l)ral foramen, and 

 the thicker grey ramus (g.r.c) twining round the psoas muscle 

 to join the last dorsal nerve (L.I).K). 



The left abdominal sympathetic lias five ganglia (text-fig. 22, 

 i-y). It gives of]' four splanchnic nerves (S.ISj which unite to 

 form a loop whence several j^lexuses radiate. And the loop 

 receives fibres from the left vagus (L.V), Farther back three 

 branches run together to form a long narrow cord, and branches 

 run thence to form the inferior mesenteric plexus (I.M.P). 

 Branches from the right .sympathetic join the latter. 



The right .sympathetic (R.S) divides into the rigjit abdominal 

 cord which has foui- ganglia (i-iv), and the splanchnic which gives 

 off the phnmic plexus (P.P) and ends in tlie right renal plexus 

 (R.R.P). 



Tlie main sympathetic cords diminish rapidly in size when 

 they enter the pelvis. And each has one ganglion between the 

 [telvic inlet and the point where the two run together at their 

 posterior extremities. No communicating lami were seen 

 running to the sacral plexuses. 



Cervical Branches of the Syinpatheiic (text-figs. 19 ife 20), 



The anterior ends of the sympathetics give communicating 

 branches to theglosso-jDharyngeal, vagus, hypoglossal, and internal 

 laryngeal nerves (6). Grey rami communicantes run to the 

 upper cervical nei'ves (C.C.P). Branches go to the pharyngeal 

 (P.P) and carotid (C.A.P) plexuses. 



The right .sympathetic gives communications to the right 

 i^ecurrent nerve (c/), and the tracheal plexus (T.P). 



Both s^anp.athetics give off cardiac nerves (C.B.8) in the neck, 

 but none ai'ise in the thorax. These meet with branches of the 

 vagus nerves in the superficial and deep cardiac plexuses. 



The Siqierficial Cardiac Flexits (text-fig. 20, S.C.P) is composed 

 of :— 



1. Two thoracic cardiac branches of the left vagus. 



2. Tln-ee fine cervical cardiac branches of the left sympathetic. 



The Dee]) Cardiac Plexus (D.CP) contains : — 



1. A cervical cardiac branch of the left sympathetic. 



2. A large cervical cardiac branch of the right sympathetic. 



3. Two thoracic cardiac branches of the right vagus. 



The Thoracic Branches of the Sym2ntthetic (text-figs. 20 k 22) 

 consist of : — 



1. Pulmonary neiwes entering the anterior and posterior 

 pulmonary plexuses (P.B.S). They do not arise as separate 

 nerves, but are given off from the cardiac nerves. 



2. Splanchnic nerves (text- fig. 22) which end in the solar plexus 

 on the left side, and the right renal plexus (R.R.P) on the right. 



