784 



THE XERVOUS SYSTEM 



divides into a luuiiljor of twigs which spread out after the manner of a fan, and 

 extend, as they approach the middle Une, from the chin to the sternum. The 

 upper two or three of these twigs unite, beneath the platysma, with the infra-mandi- 

 bular branch of the facial, and thus form loops. From the terminal branches of 

 the nerve numerous twigs ])ierce the platysma to end in the skin of the front part of 



the neck. 



Descending branches. — These are derived from the third and fourth cervical 

 nerves, and arise under cover of the sterno-mastoid. At their conmiencement they 

 are usually united with the muscular branches destined for the trapezius. They 



Fig. 454.— Superficial Beanches of the Cervical Plexus. 

 (After Hirschfeld aud Leveille. ) 



POSTERIOR 



AURICULAR 

 NER VE 



FACIAL NERVE 



AURICULAR BR. OF 



GREAT AURICULAR ^ 



INFRAMANDIB ULAR 



SUPERFICIAL CERVICAL 

 BRANCHES OF SUPER 

 FICIAL CERVICAL 

 NERVE 



SUPRA STERNA L 



\ BRANCHES OF 

 y GREA T 

 \ AURICULAR 



GREAT OCCIPITAL 



LESSER OCCIPITAL 



GREAT AURICULAR 

 MASTOID BR. OR Slid 



SMALL OCCIPITAL 

 SPINAL ACCESSORY 



TWIGS FROM THE 

 MASTOID BRAyCff 



BR. TO LEVATOR 



ANGULI SCAPULJi 

 SUPRA- A CROMIAL 



SUPRA CLA VICULA R 



BRANCHES TO 



TRAPEZIUS 



SUPRACLA VICULAR 



>^^^^. 



become superficial at the posterior liorder of the storno-mastoid, about the centre 

 of that muscle, and are termed sui)ra-sternal, supra-clavicular, and supra-acronnal 

 nerves. (1) The supra-sternal twigs are small, and cross over tbe clavicular origin 

 of the sterno-mastoid to reach the integument over the upper part of the manu- 

 brium sterni. They also supply the sterno-clavicular joint. (2) The supra- 

 clavicular nerves,' of considerable size, cross in front of the middle third of the 

 clavicle under cover of the platysma, and are distributed to the skin, covermg 

 the upper ]mrt of the pectoralis major as low as the third rib. (3) The supra- 

 acromial branches cross the clavicular insertion of the trapezius and the acromion 



