338 DISSECTION OF THE EABBIT 



4. The cervical sympathetic liea alongside the trachea, to 



the inner side of the carotid artery, and in close 

 proximity to the depressor nerve. 



About the level of the angle of the jaw, and dorsal 

 to the stylo-hyoid muscle, it has a small oval swell- 

 ing, the superior cervical ganglion ; and at the pos- 

 terior end of the neck, a short distance in front of the 

 subclavian artery on either side, there is a similar 

 swelling, the inferior cervical ganglion. 



The sympathetic nerves are of a pale pinkish cohur, and 

 are not nearly so easy to see as the white cords of the pneumo- 

 gastric and its branches. 



5. The great auricular nerve is a large branch of the third 



spinal nerve, given off immediately after the nerve 

 emerges from the spinal canal, between the second 

 and third cervical vertebrae. It runs vertically up- 

 wards to the base of the ear, lying along the posterior 

 border of the parotid gland, and about half an inch 

 behind the angle of the jaw : it then continues its 

 course along the outer surface of the pinna of the 

 ear, as far as its tip, lying just beneath the skin. 



TJie nerve can readily be felt as a cord running along the 

 pinna, or seen by holding the ear up to the light, and looking 

 through it. 



Having determined its position in one of these ways, cut 

 down upon it, and follow it to the tip of the ear, and down- 

 wards to its point of emergence from the vertebral canal. 



6. The phrenic nerve is a branch of the fourth cervical 



nerve, which arises just beyond the point of emer- 

 gence of this nerve from the neural canal, and runs 

 back alongside the vertebral column. Entering the 

 thorax it continues its course backwards, lying 

 between the heart and the lungs on either side, and 

 ends in the diaphragm, which it supplies with motor 

 fibres. 



In the neck it crosses the roots of the hinder 

 cervical nerves almost at right angles. It receives 



