822 



THE NERVOUS SYSTEM 



by the great auricular, small occipital, and supraclavicular branches of the cervical 

 plexus (fig. 469a), and posteriorly the skin of the neck is sui)plied by the small 

 occipital nerve and by the internal branches of the posterior primary divisions of 

 the cervical nerves from the second to the sixth inclusive (fig. 469b). 



Fig. 469a. — Diagram of the Cutaxeous Nekve Areas of the Head axd Neck. 



Red — First division of fifth. White — Second division of fifth. 



Blue — Third division of fifth. 

 Dark shading — Posterior primary division of cervical nerve. 



Oblique shading — Ascending and transverse superficial branches of cervical plexus. 

 Transverse shading — Descending superficial branches of cervical plexus. 

 It must be understood the boundaries of each area are not distinct ; wherever two areas meet they overlap. 



SMALLEST 

 OCCIPITAL 



TEMPO RA L 

 SUPRA 

 TROCHLEAR 



LACHRYMAL 



INFRA 

 'ROC H LEAR 



NASAL 



\ 



The Cutaneous Areas of the Body 



The skin over the anterior aspect of the body as far down as the second rib is 

 supplied by the suprasternal and supraclavicular branches of the cervical plexus, 

 which contain filaments from the third and fourtli cervical nerves (fig. 469b); from 

 the second rib to the lower part of the abdominal wall it receives the anterior cuta- 

 neous branches, and the anterior divisions of the lateral cutaneous l)ranches of the 

 dorsal nerves except the first, second, and twelfth (fig. 469b); and the skin over the 



