038 THE CERVICAL NERVES AND PLEXUS. 



I. SUPERFICIAL ASCENDING BRANCHES. 



SUPERFICIAL CERVICAL NERVE. 



This nerve takes origin from the second and third cervical nerves, turns 

 forward over the sterno-mastoid about the middle, and, after perforating the 

 cervical fascia, divides beneath the platysma myoides into two branches, 

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



a. The upper branch gives an ascending twig which accompanies the external jugular 

 vein, and communicates freely with the facial nerve (cervico-facial division) ; it is then 

 transmitted through the platysma to the surface, supplying that muscle, and ramifies 

 in the integument of the upper half of the neck on the fore part, filaments reaching as 

 high as the lower maxilla. 



b. The lower branch likewise pierces the platysma, and is distributed below the 

 preceding, its filaments extending in front as low as the sternum. 



The superficial cervical nerve may arise from the plexus in the form of two or more 

 distinct branches. Thus Valentin describes three superficial cervical nerves, which he 

 names superior, middle, and inferior. (" Sommerring v. Bau," &c.) 



While the superficial cervical nerve ramifies over the platysma myoides, the facial 

 nerve is beneath the muscle. According to Valentin many anastomotic arches are 

 formed on the side of the neck between those two nerves, as well as between the 

 branches of the former, one with another. 



GREAT AURICULAR NERVE. 



This nerve winds round the outer border of the sterno-mastoid, and is 

 directed obliquely upwards beneath the platysma myoides, between the 

 muscle and the deep fascia of the neck, to the lobe of the ear. Here the 

 nerve gives a few small branches to the face, and ends in the auricular 

 and mastoid branches. 



a. The auricular branches are directed to the back of the external ear, on which 

 they ramify, and are connected with twigs derived from the facial nerve. One 

 of these branches reaches the outer surface of the ear by a fissure between the 

 antihelix and the concha. A few filaments are supplied likewise to the outer part 

 of the lobule. 



b. The mastoid branch is united to the posterior auricular branch of the facial 

 nerve, and ascends over the mastoid process to the integument behind the ear. 



c. The facial branches of the great auricular nerve, which extend to the integu- 

 ments of the face, are distributed over the parotid gland. Some slender filaments 

 penetrate deeply through the substance of the gland, and communicate with the facial 

 nerve. 



SMALL OCCIPITAL NERVE. 



The smaller occipital nerve varies in size, and is sometimes double. It 

 springs from the second cervical nerve, and is directed almost vertically to 

 the head along the posterior border of the sterno-mastoid muscle. Having 

 perforated the deep fascia near the cranium, the small occipital nerve is 

 continued upwards between the ear and the great occipital nerve, and ends 

 in cutaneous filaments which extend upwards in the scalp ; it communicates 

 with branches from the larger occipital nerve, as well as with the posterior 

 auricular branch of the facial. It appears to supply sometimes the occipito- 

 frontalis muscle. 



The auricular branch (ram. auricularis superior posterior) is distributed to the 

 upper part of the ear on the posterior aspect, and to the elevator muscle of the auricle. 

 This auricular branch is an offset from the great occipital nerve, when the small 

 occipital is of less size than usual. 



