506 CERVICAL NERVES. 



oblongata, between the corpora pyramidalia and the corpora 

 olivaria. Three or four fasciculi of distinct filaments, unite 

 to form it. Thus composed, it proceeds to the anterior condy- 

 loid foramen of the occipital bone, and passes through the 

 dura mater. It seems firmly united, by the cellular mem- 

 brane, to the eighth pair, and to the first ganglion of the 

 sympathetic, soon after it passes from the occipital bone. It 

 is either connected to the sub-occipital nerve by a small 

 ramification, or it joins a branch which proceeds from the 

 sub-occipital to the cervical, and bends round the transverse 

 process of the atlas. It passes between the internal carotid 

 artery and the internal jugular vein, and crosses the external 

 carotid at the origin of the occipital artery. At this place it 

 generally sends downwards a large branch which is called the 

 Descendens Noni. Passing forwards, it is on the outside of 

 the posterior portion of the digastric muscle, and inclines 

 downwards ; but near the tendon of the muscle it turns 

 upwards, and proceeds on the inside of the mylo-hyoideus, 

 where it divides into ramifications, which, at the anterior 

 edge of the hyo-glossus muscle, begin to enter the substance 

 of the tongue, between the genio-glossus and the lingualis 

 muscles. 



Some of the branches of this nerve unite with those of the 

 lingual branch of the fifth pair. Others are distributed to 

 almost all the muscles connected with the tongue. 



It also interchanges filaments of communication, with the 

 pneumogastric and spinal accessory at the base of the skull 

 behind the internal jugular vein. Branches likewise pass 

 between it and the superior cervical ganglion. 



The branch called descendens noni passes down in the 

 course of the common carotid artery, and sends fibrils in 

 its progress to the upper portions of the orno-hyoid and sterno- 

 thyroid muscles ; it unites with ramifications of various sizes 

 from the first, second, and third cervical nerves, which form a 

 bow under the sterno-mastoid muscle, from which ramifications 

 go to the lower portions of the sterno-hyoid and thyroid muscles, 

 and of the omo-hyoid. 



