854 



THE NERVES. 



general manner, because of their diversity, 

 each region of the spine. 



We will study them successively in 



Fig. 464. 



Article I. — Cervical Nerves (8 Pairs). 



Superior Branches. — The Jirst (the suboccipital of Willis) passes through 

 the superior foramen of the atlas, in company with the cerebro-spinal artery. 

 It arrives in the space between the small oblique muscle of the head and the 

 posterior straight muscles, and divides immediately into several divergent 

 branches, which are distributed to the three above-named muscles, the anterior 

 extremity of the complexiis, and the cervico- and temporo- 

 auricular muscles. The ramuscule sent to the latter 

 ascends within the concha, and breaks up into several 

 filaments that supply the skin of the external ear. 



The second immediately furnishes some ramuscules 

 to the obliquus capitis posticus muscle, beneath which it 

 is placed, as well as to the anterior oblique. It is after- 

 wards directed backwards, comporting itself like the suc- 

 ceeding ones. 



These diminish in volume from the third to the eighth. 

 All pass through the intertransversales muscle, and 

 divide into several branches, which are distributed to the 

 muscles and integuments of the superior cervical region. 

 Among these, the superficial, which are almost rudimentary 

 in the two last pairs, reach the inner face of the splenius. 

 The others, deep and more voluminous, cross the semi- 

 spiiialis colli, and, dividing, ascend between the complexus 

 and cervical ligament, to near the superior border of that 

 large elastic layer. They generally intercommunicate by 

 several filaments, and in this way form a network on the 

 inner face of the complexus, which Girard named the deep 

 cervical plexus. 



Inferior Branches. — These branches augment in 

 size from the first to the last, and separate into two 

 perfectly distinct groups. The divisions of the first six 

 cover the lateral and anterior parts of the neck, as well 

 as the muscles of the breast. Usually anastomosing with 

 each other by long communicating branches, they in this 

 waj form a vast nervous network traversed by two important nerves — the spinal 

 accessory and cervical filament of the facial ; this is the superficial cervical plexus. 

 The other two are united with the preceding by a filament passing between the 

 sixth and seventh, soon l)ecoming confounded with each other, as well as with 

 the two first branches of the dorsal region ; they constitute — in common with the 

 latter — the brachial plexus. 



Without saying any more as to the disposition of this double plexus, we will 

 pass to the particular description of each cervical pair of nerves. 



First. — Deeply situated beneath the transverse process of the atlas, this nerve 

 leaves the anterior foramen of that vertebra, and accompanies the occipital artery 

 and vein to place itself immediately between the rectus capitis anticus minor and 

 rectus lateralis muscles. It then crosses the rectus capitis anticus major and the 

 spinal accessory nerve, which it separates ; and arrives, after describing a slight 



GANGLION OF A SPINAL 

 NERVE FROM THE LUM- 

 BAR REGION OF A 

 POPPY. 



a, Superior root ; 6, in- 

 ferior root; c, ganglion 

 on the superior root; 



d, e, junction of the 

 fibres from the inferior 

 and superior roots with 

 those comins; from the 

 ganglion ; d, superior 

 trunk of spinal nerve ; 



e, its inferior trunk. 



