564 SPINAL NERVES. ___,,. 



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SUPERFICIAL BRANCHES OF THE CERVICAL PLEXUS. 



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 forwards behind the external jugular vein to the anterior border of that 

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

 two branches, which are distributed to the anterior and lateral parts of the neck. 



The ascending branch gives a filament, which accompanies the external jugular 

 vein; it then passes upwards 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 this muscle, supply it, and are distri- 

 buted to the integument of the upper half of the neck, at its fore part, as high 

 as the chin. 



The descending branch pierces the Platysma, and is distributed to the integument 

 of the side and front of the neck, as low as the sternum. 



This nerve is occasionally represented by two or more filaments. 



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

 from the second and third cervical nerves, winds Tound 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 numerous 

 branches. 



The facial branches pass across the carotid, and are distributed to the integu- 

 ment of the face ; others penetrate the substance of the gland, and communicate 

 with the facial nerve. 



The posterior or auricular branches ascend vertically to supply the integument 

 of the back part of the pinna, communicating with the auricular branches of the 

 facial and pneumogastric nerves. 



The mastoid branch joins the posterior auricular branch of the facial, and, crossing 

 the mastoid process, is distributed to the integument behind the ear. 



The Occipitalis Minor arises from the second cervical nerve ; it curves round 

 the posterior border of the Sterno-mastoid above the preceding, and ascends 

 vertically along the posterior border of this muscle to the back part of the side 

 of the head. Near the cranium it perforates the deep fascia, and is continued 

 upwards along the side of the head behind the ear, supplying the integument and 

 Occipito-frontalis muscle, and communicating with the occipitalis major, auricu- 

 laris magnus, and posterior auricular branch of the facial. 



This nerve gives off an auricular branch, which supplies the Attollens aurem 

 and the integument of the upper and back part of the auricle. This branch is 

 occasionally derived from the great occipital nerve. The occipitalis minor varies 

 in size ; it is occasionally double. 



The Descending or Supra-clavicular branches arise from the third and fourth 

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

 descend in the interval between this muscle and the Trapezius, and divide into 

 branches, which are arranged, according to their position, into three groups. 



The inner or sternal branch crosses obliquely over the clavicular and sternal 

 attachments of the Sterno-mastoid, and supplies the integument as far as the 

 median line. 



The middle or clavicular branch crosses the clavicle, and supplies the integu- 

 ment over the Pectoral and Deltoid muscles, communicating with the cutaneous 

 branches of the upper intercostal nerves. Not unfrequently, the clavicular 

 branch passes through a foramen in the clavicle, at the junction of the outer with 

 the inner two-thirds of the bone. 



The external or acromial branch passes obliquely across the outer surface of the 

 Trapezius and the acromion, and supplies the integument of the upper and back 

 part of the shoulder. 



