CERVICAL PLEXUS. 457 



The anterior branches of the fifth, sixth, seventh, and eighth cervical 

 nerves will be described with the brachial plexus, of which they form 

 a part. 



CERVICAL PLEXUS. 



The cervical plexus is constituted by the loops of communication, 

 and by the anastomoses which take place between the anterior 

 branches of the four first cervical nerves. The plexus rests upon the 

 levator anguli scapulae, posterior scalenus, and splenius muscle, and is 

 covered in by the sterno-mastoid and platysma. 



The Branches of the cervical plexus may be arranged into three 

 groups, superficial ascending, superficial descending ; and deep 



f ( Superficialis colli, 



j Ascending, < Auricularis magnus, 

 Superficial <^ ( Occipitalis minor. 



S Acromiales, 



f Communicating branches, 



Been < Muscular > 



j Communicans noni, 

 (.Phrenic. 



The Superficialis colli is formed by communicating branches from 

 the second and third cervical nerves ; it curves around the posterior 

 border of the sterno-mastoid and crosses obliquely behind the external 

 jugular vein to the anterior border of that muscle, where it divides 

 into an ascending and a descending branch ; the descending branch is 

 distributed to the integument on the side and front of the neck, as 

 low down as the clavicle ; the ascending branch passes upwards to the 

 submaxillary region, and divides into four or five filaments, some of 

 which pierce the platysma myoides and supply the integument as 

 high up as the chin and the lower part of the face, while others form 

 a plexus with the descending branches of the facial nerve beneath the 

 platysma. One or two filaments from this nerve accompany the 

 external jugular vein. 



The Auricularis magnus, the largest of the three ascending branches 

 of the cervical plexus, also proceeds from the second and third cervical 

 nerve ; it curves around the posterior border of the sterno-mastoid 

 and ascends upon that muscle, lying parallel with the external jugular 

 vein, to the parotid gland, where it divides into an anterior and a poste- 

 rior branch. The anterior branch is distributed to the integument 

 over the parotid gland, to the gland itself, communicating with the facial 

 nerve, and to the external ear. The posterior branch pierces the parotid 

 gland and crosses the mastoid process, where it divides into branches 

 which supply the posterior part of the pinna and the integument 

 of the side of the head, and communicate with the posterior auricular 



