THE SYMPATHETIC NERVE. 479 



the carotid artery and internal jugular vein. It is commonly 

 said to be enclosed in the sheath of these great vessels, but the 

 statement is loose and inaccurate, as it is fastened to the front 

 surface of the longus colli muscle by cellular substance distinct 

 from the sheath, as may be manifested by pushing a Hiife 

 handle between them and raising up the sheath. The cord 

 which comes down from the carotid canal is close to the pneu- 

 mogastric and hypoglossal nerves. Having formed the first 

 cervical ganglion, it descends as mentioned; and, opposite to 

 the space between the fifth and sixth cervical vertebrae, it is 

 again enlarged into the Middle Cervical Ganglion, which is 

 much smaller and more irregular than the first. The sympa- 

 thetic is then traced with some difficulty, in consequence of 

 the numerous branches coming from it; but, with attention, a 

 trunk may be found as the continuation of it. This trunk 

 passes to the interval between the head of the first rib and the 

 transverse process of the last cervical vertebra, and there en- 

 larges into another ganglion, called Inferior Cervical or First 

 Dorsal. 



To understand well the connexions of the sympathetic in the 

 neck, each of the cervical ganglions must be studied particu- 

 larly. 



1st. The Superior Cervical Ganglion varies considerably in 

 its extent; commencing very generally opposite to the second 

 cervical vertebra, it is sometimes elongated to the lower part 

 of the third and even of the fourth. In cases of unusual elon- 

 gation, it is smaller than in others. 



It sends off, from its external margin, several filaments, 

 about four, which cross the anterior face of the rectus anti- 

 cus major muscle, and terminate by anastomosing with the 

 anterior fasciculus of the occipital nerve and of the first three 

 cervical: when the ganglion is short, the two lower filaments 

 come from the sympathetic below it, instead of from the gan- 

 glion. 



Several filaments also proceed from this ganglion to the con- 

 tiguous muscles on the vertebral column, to the pharynx, to the 

 larynx, and to the thyroid gland. 



This ganglion also sends off what are called its Anterior 



