400 SPECIAL ANATOMY. 



the bronchi. Some filaments are lost in the pulmonary artery. 

 Its posterior filaments belong to n. sympathicus, from its three 

 superior ganglia. 



5. Plexus cesophageus inferior, formed by the internal principal 

 trunk of the vagus, which descends farther on the oesophagus be- 

 low the bronchi, entwines around it, and penetrates between its 

 coats. The right vagus passes more towards the posterior (pi. 

 ozsoph. post.) ; the left more towards the anterior surface (pi. an- 

 terior). Both anastomose with each other by large branches. 



646. (IV.) The abdominal portion of the Vagus. 



The right trunk enters behind, the left before the oesophagus, 

 through the foram. cesophageum. Each is lost in a fasciculus, 

 rami gastrici, and forms a plexus gastricus. 



1. Plex. gastricus anterior, formed by the left n. vagus, lies 

 upon the anterior surface along the small curvature from the 

 Cardia to the Pylorus; gives branches to the fundus ventri- 

 culi; to the small omentum as far as fossa transversa 



2. Plexus gastricus posterior, formed by the right n. vagus, 

 lies behind the cardia, is smaller than 1, and passes, princi- 

 pally, into the plex. Solaris. 



Connexions of the n. vagus : with n. trigeminus, facialis, 

 glosso-pharyngeus, accessorius Willis., hypoglossus, cervicatt. su- 

 perr. 3, and sympathicus. 



Function. The vagus is entirely sensitive until its connexion 

 with n. accessor. Willis., then a motor nerve likewise. 



647. XL JV. accessorius Willisii, the spinal accessory Nerve. 



Origin : from the posterior part of the central columns of the 

 spinal cord, between the posterior roots of the fourth to the sixth 

 cervical nerves (sometimes even deeper) and lig. denticulatum ; 

 with six to seven radical filaments, which are strengthened by the 

 posterior roots of the first (to the third) cervical nerves, but only 

 pass in a sheath with them, and often present a small ganglion, 

 but which belongs to the cervical nerves. Course : upwards on 

 the sides of the spinal marrow, always becoming more distant 

 from it ; over the first cervical nerve, strengthened by some fila- 

 ments, through the foram. magnum to the cranial cavity. It 

 here passes in a curve downwards, forwards, and outwards, en- 

 veloped by the dura mater, to the vagus, passes into its sheath, 

 on the outer side, and behind it, through foram. jugul-are, pass- 



