THE TENTH OR PNEUMOGASTRIC NERVE. 



819 



Spinal accessory. 



ryngeal 



laryngeal. 



Tenth Pair (Figs. 491, 492). 



The Tenth or Pneumogastric Nerve (nervus vagus or par vagum) has a more 

 extensive distribution than any of the other cranial nerves, passing through the 

 neck and thorax to the upper 



part of the abdomen. It is Glosso-pharyngeal. 



composed of both motor and 

 sensory fibres. It supplies the 

 organs of voice and respiration 

 with motor and sensory fibres, 

 and the pharynx, oesophagus, 

 stomach, and heart with motor 

 fibres. Its superficial origin is 

 by eight or ten filaments from 

 the groove between the olivary 

 and the restiform body below 

 the glosso-pharyngeal ; its deep 

 origin may be traced through 

 the fasciculi of the medulla to 

 its nucleus of gray matter in the 

 lower part of the floor of the 

 fourth ventricle beneath the ala 

 cinerea below and continuous 

 with the nucleus of origin of 

 the glosso-pharyngeal. The fil- 

 aments become united and form 

 a flat cord, which passes outward 

 beneath the flocculus to the jug- 

 ular foramen, through which it 

 emerges from the cranium. In 

 passing through this opening the 

 pneumogastric accompanies the 

 spinal accessory, being contained 

 in the same sheath of dura mater 

 with it, a membranous septum 

 separating it from the glosso- 

 pharyngeal, which lies in front 

 (Fig. 386). The nerve in this 

 situation presents a well-marked 

 ganglionic enlargement, which is 

 called the jugular ganglion, or 

 the ganglion of the root of the 

 pneumogastric : to it the acces- 

 sory part of the spinal accessory 

 nerve is connected by one or two 

 filaments. After the exit of the 

 nerve from the jugular foramen 

 the nerve is joined by the acces- 

 sory portion of the spinal acces- 

 sory, and enlarged into a second 

 gangliform swelling, called the 

 ganglion inferius, or the gan- 

 glion of the trunk of the nerve, 

 over which the fibres of the spi- 

 nal accessory pass unchanged, 

 being principally distributed to the pharyngeal and superior laryngeal branches 

 of the vagus ; but some of the filaments from it are continued into the trunk of 



FIG. 492. Course and distribution of the ninth, tenth, and 

 eleventh nerves. 



