THE SYMPATHETIC NERVOUS SYSTEM 



36? 



fibers which constitute longitudinal commissures and connect the various 

 ganglia of the head with the ganglionated cord of the trunk region. The 

 small, cranial sympathetic ganglia are probably all derived from the anlage 

 of the semilunar ganglion (Fig. 366). The ciliary ganglion is related by a 

 ramus communicans to the ophthalmic division of the trigeminal nerve and 



FIG. 366. The sympathetic system in a 16 mm. human embryo (Streeter in Lewis and 

 Stohr). X 7. The ganglionated trunk is heavily shaded. The first and last cervical, thoracic, 

 lumbar, sacral and coccygeal spinal ganglia are numbered, a., Aorta; ace., accessory nerve; 

 car., carotid artery; cil., cilliary ganglion; coe., cceliac artery; Ht., heart; nod., nodose gang- 

 lion; ot., otic ganglion; pet., petrosal ganglion; s-m., submaxillary ganglion; s.mes., superior 

 mesenteric artery; sph-p., spheno-palatine ganglion; spl., splanchnic nerve; 5/., stomach. 



receives fibers from the oculomotor nerve. Its cells are apparently de- 

 rived entirely from the semilunar ganglion. The spheno-palatine, sub- 

 maxillary, and otic ganglia probably take their origin from migrating cells 

 of the semilunar ganglion, but as they are connected with the geniculate 

 ganglion of the facial nerve it is possible that the latter contributes to 

 their formation also. The spheno-palatine ganglion is connected directly 



