THE CERVICAL PLEXUS. 



637 



and deep ; the superficial consisting of those which ramify over the cervical 

 fascia, supplying the integument and some also the platysma ; the deep 

 comprising branches which are distributed for the most part to the muscles. 

 The superficial nerves may be subdivided into ascending and descending ; 

 the deep nerves into an internal and external series. 



Fig. 423. DIAGRAMMATIC Fig 423. 



OUTLINE OP THE FIRST 

 PARTS OP THE CERVICAL 

 AND UPPER DORSAL 

 NERVES, SHOWING THE 

 CERVICAL AND BRACHIAL 

 PLEXUSES. J 



The nerves are separated 

 from tlie spinal cord at 

 their origin and are sup- 

 posed to be viewed from 

 before. Cl, is placed op- 

 posite the roots of the first 

 cervical or suboccipital 

 nerve, and the roman num- 

 bers in succession from IF, 

 to VIII, opposite the roots 

 of the corresponding cer- 

 vical nerves ; DI, is placed 

 opposite to the roots of the 

 first dorsal nerve, and II, 

 and IK, opposite the second 

 and third nerves ; the origin 

 of the posterior primary 

 branch is shown in all the 

 nerves; of these p 2, indi- 

 cates the great occipital 

 from the second, and ^;3, 

 the smallest occipital nerve 

 from the third. In con- 

 nection with the cervical 

 plexus the following indica- 

 tions are given ; 1, anterior 

 primary branch of the 

 first cervical nerve and loop 

 of union with the second 

 nerve ; 2, lesser occipital 

 nerve proceeding in this 

 case from the second cervi- 

 cal nerve, more frequently 

 from the second and third ; 

 3, great auricular nerve 

 from the second and third ; 



3', superficial cervical nerve from the third; 3 n, communicating branches to the descen- 

 dens noni from the second and third ; 3 s, communicating to the spinal-accessory from the 

 second, third, and fourth ; 4, supraclavicular and supraacromial descending nerves : 

 the loops or arches of communication between the four upper cervical nerves, and between 

 the fourth and fifth are shown ; 4', the phrenic nerve springing from the fourth and fifth 

 nerves. In connection with the nerves of the brachial plexus and the remaining nerves 

 the following indications are given V, to VIII 7 , and D', the five roots of the brachial 

 plexus ; 5, the rhomboid nerve ; 5', suprascapular ; 5", posterior thoracic ; 6, nerve to the 

 subclavius muscle; 7, 7, inner and outer anterior thoracic nerves; 8, 8', 8", upper and 

 lower subscapular nerves. In the larger nerves proceeding to the shoulder and arm from 

 the plexus, those of the anterior division are represented of a lighter shade, those belonging 

 to the posterior division darker ; ec, external cutaneous or musculo-cutaneous ; ?/i, median; 

 M, ulnar, ic, internal cutaneous ; w, nerve of Wrisberg ; r, musculo -spiral ; c, circum- 

 flex ; i, intercostal nerves ; i', lateral branch of the same ; ih, intercosto-humeral nerves. 



Ill 



