137 
The single root of the ixth (r. zz.) leaves the medulla 
much below and somewhat behind the root of the lateralis. 
It is situated quite by itself, and distinct from any other 
root. it passes almost straight backwards above and 
slightly to the inner side of the posterior division of the 
acusticus, and becomes related to the R. acust. ampulle 
posterioris as above described. It then courses almost 
straight outwards and downwards, first between the 
sacculus and utriculus, and afterwards between the 
sacculus and the skull. It now bends forwards and down- 
wards, passes through its foramen (represented by a ring 
in the chart), and enters the large ganglion (g. za.) lying 
just outside the skull. 
Before entering the ganglion, and just after leaving 
the foramen, the root gives off above a motor branch. 
This passes forwards over the top of the ganglion, and 
enters the R. post-trematicus, thus accounting for most 
of the motor fibres of the glossopharyngeus. 
The peculiar course of the root first backwards and 
then forwards is due to the position of the ear. That is 
to say it passes straight backwards until it can escape 
outwards through the fissure between the sacculus and the 
utriculus behind. 
The nerve arising from the ganglion is very flattened 
and ribbon-like, and soon splits into two large nerves—an 
upper R. post-trematicus and a lower Jacobson’s 
anastomosis (Jac. anast.). The latter passes forwards, 
gives off a motor branch below, the fibres of which have 
previously traversed the ganglion to reach it, and finally 
anastomoses with the post-trematicus vii., which see for 
its subsequent course. The relations of the sympathetic 
to the glossopharyngeus are described with the former 
system. : 
R. post-trematicus (post. t.)—Courses forwards 
