762 THE NERVOUS SYSTEM. 



! Communicating. 



r Muscular. 



n vi- 



Commumcantes hypoglossi. 

 Phrenic. 

 L Communicating. 



TVT 1 



Muscular. 



Superficial Branches of the Cervical Plexus. 



The Occipitalis minor (Fig. 415) arises from the second cervical nerve, some- 

 times also from the third ; it curves round the posterior border of the Sterno- 

 mastoid, and ascends, running parallel to the posterior border of the muscle, to 

 the back part of the side of the head. Near the cranium it perforates the deep 

 fascia, and is continued upward along the side of the head behind the ear, supply- 

 ing the integument, and communicating with the occipitalis major, the auricularis 

 magnus, and with the posterior auricular branch of the facial. 



This nerve gives off an auricular branch, which supplies the integument of 

 the upper and back part of the auricle, communicating with the mastoid branch 

 of the auricularis magnus. This branch is occasionally derived from the great 

 occipital nerve. The occipitalis minor varies in size ; it is occasionally double. 



The Auricularis Magnus is the largest of the ascending branches. It arises 

 from the second and third cervical nerves, winds round the posterior border of 

 the Sterno-mastoid, and, after perforating the deep fascia, ascends upon that 

 muscle beneath the Platysma to the parotid gland, where it divides into facial, 

 auricular, and mastoid branches. 



The facial branches pass across the parotid, and are distributed to the integ- 

 ument of the face over the parotid gland ; others penetrate the substance of the 

 gland and communicate with the facial nerve. 



The auricular branches ascend to supply the integument of the back of 

 the pinna, except at its upper part, communicating with the auricular branches 

 of the facial and pneumogastric nerves. A filament pierces the pinna to reach 

 its outer surface, where it is distributed to the lobule and lower part of the 

 concha. 



The mastoid branch communicates with the occipitalis minor and the posterior 

 auricular branch of the facial, and is distributed to the integument behind the ear. 



The Superficialis Colli arises from the second and third cervical nerves, turns 

 round the posterior border of the Sterno-mastoid about its middle, and, passing 

 obliquely forward beneath the external jugular vein to the anterior border of the 

 muscle, perforates the deep cervical fascia, and divides beneath the Platysma into 

 two branches which are distributed to the antero-lateral parts of the neck. 



The ascending branch gives a filament which accompanies the external jugular 

 vein ; it then passes upward to the submaxillary region, and divides into branches, 

 some of which form a plexus with the cervical branches of the facial nerve beneath 

 the Platysma ; others pierce that muscle and are distributed to the integument of 

 the upper half of the neck, at its fore part, as high as the chin. 



The descending branch (occasionally represented by two or more filaments) 

 pierces the Platysma, and is distributed to the integument of the side and front 

 of the neck, as low as the sternum. 



The Descending or supraclavicular branches arise from the third and fourth 

 cervical nerves : emerging beneath the posterior border of the Sterno-mastoid, 

 they descend in the posterior triangle of the neck beneath the Platysma and deep 

 cervical fascia. Near the clavicle they perforate the fascia and Platysma to become 

 cutaneous, and are arranged, according to their position, into three groups. 



The inner or suprastemal branches cross obliquely over the external jugular 

 vein and the clavicular and sternal attachments of the Sterno-mastoid, and supply 

 the integument as far as the median line. They furnish one or two filaments to 

 the sterno-clavicular joint. 



