

NERVOUS TRUNKS IN MAN. 353 



General Arrangement of the Nervous Trunks in Man, 

 Fig. 8. 



The terms cerebellum, cerebrum, and others belonging 

 to several divisions of the organs of the sensorial func- 

 tions, are explained in connection with the figure of the 

 brain, page 204. The figure from a recent London 

 work, of Dr. Carpenter, shows the general distribution 

 of the nerves on the posterior division of the body, but 

 for the present purpose it is thought necessary to name 

 the principal trunks only. 



At a are seen the two hemispheres of the cerebrum ; 

 and at 6, those of the cerebellum. The facial nerve, 

 the principal one of the face, c, ramifies in every direc- 

 tion, and receives different names, according to the parts 

 it supplies, but does not endow these parts with the least 

 sensibility, being nerves of motion. The spinal cord, d, 

 proceeds from the brain down the back, sending off 

 branches to all the adjoining parts, as represented. The 

 spinal nerves are perfectly regular in their number and 

 distribution. Their number is thirty-two on each side, 

 making their whole number sixty-four. 



It has already been stated, page 224, that every mus- 

 cle is supplied with two nerves, one for muscular mo- 

 tion, the other for sensation. Now late experiments have 

 proved that the two sets arise from opposite parts of the 

 spinal cord, those for sensation arising from the posteri- 

 or, and those of motion from the anterior portions. 



The brachial plexus, e, which supplies the arm and 

 hand, is a sort of nervous net-work, originating from the 

 spinal cord by several roots. From this plexus is de- 

 rived the median nerve, f, the ulnar nerve, g, and the 

 internal cutaneous nerve, h. The sciatic plexus, i, call- 

 ed the great sciatic nerve, being the largest in the body, 

 divides, as it descends, into several branches, among 

 which is the tibial nerve, m, peroneal, or fbular nerve, 

 TZ, and the external saphenous nerve, o. 



The spinal cord gives off branches which supply the 

 intercostal muscles, or those between the ribs. These 

 are called the intercostal nerves, and are seen at j t as 

 well as above and below that point. These supply the 



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