THE CERVICAL PLEXUS 



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each receive a gray ramus communicans, those for the fifth and sixth being derived 

 from the middle, and those for the seventh and eighth from the inferior, cervical 

 ganglion of the sympathetic. 



THE CERVICAL PLEXUS (PLEXUS CERVICALIS) (Figs. 754, 755). 



The cervical plexus is formed by the anterior divisions of the four upper cervical 

 nerves. It is situated opposite the four upper cervical vertebrae, resting upon the 

 Levator anguli scapulae and Scalenus medius muscles, and covered in by the 

 Sternomastoid. 



Its branches may be divided into two groups, superficial and deep, which may 

 be thus arranged: 



Superficial 



I Ascending 

 Transverse 



Deep 



(Small occipital 



\ Great auricular 



Superficial cervical 



[ Sternal 



Descending or Supraclavicular j Clavicular 



I Acromial 



f with hypoglossal 



Communicating < with vagus 



I with sympathetic 

 f Rectus lateralis .... 

 j Anterior Recti .... 

 1 Communicantes hypoglossi 



[ Phrenic 



f Communicating with spinal accessory . 



' Sternomastoid 



Trapezius 



Levator anguli scapulae 

 Scalenus medius 



r Internal 



'External 



. Muscular 



Muscular 



I, 



2,C. 



2. 3, C. 

 2,3,C. 

 3,4,C. 



3. 4, C. 

 3, 4, C. 

 1,2, C. 

 1, 2, C. 



2,3,4,C. 



2. 3, C. 

 3, 4, 5, C. 

 2, 3, 4, C. 



2,C. 



3. 4, C. 

 3, 4, C. 

 3, 4, C. 



The Superficial Branches of the Cervical Plexus. The Small Occipital Nerve 



(n. occipitalis minor) (Fig. 754) arises from the second cervical nerve, sometimes 

 also from the third; it curves around the posterior border of the Sternomastoid, 

 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, supplying 

 the integument, and communicating with the great occipital, great auricular, 

 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 great auricular. The auricular branch is occasionally derived from the 

 great occipital nerve. The small occipital varies in size ; it is occasionally double. 



The Great Auricular Nerve (n. auricidaris magnus) (Fig. 754) is the largest of 

 the ascending branches. It arises from the second and third cervical nerves, 

 winds around the posterior border of the Sternomastoid, 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 are distributed to the integument 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 vagus 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 small occipital and the posterior 



