THE DEEP CONNEXIONS OF THE CRANIAL NERVES. 483 
encountered the moment the boundary line between the medulla and pons is 
passed, and the region immediately above the inferior olivary nucleus is reached. 
At first it lies so deeply in the tegmentum of the pons that it actually rests upon 
the dorsal aspect of the corpus trapezoides; but a little farther up the superior 
olive comes into view, and insinuates itself between the facial nucleus and the 
trapezial fibres. The upper part of the nucleus is in this way tilted somewhat 
backwards, and thus comes to He on the dorsal and outer aspect of the superior 
olive. 
The facial nucleus is situated close to the place where the nerve emerges from 
the brain, but the ‘nerve does not at once pass to this point of exit. It pursues 
a long and devious path within the pons before it finally reaches the METS: 
This intrapontine part of the nerve may be divided into three parts, viz.: (1) a 
radicular part, (2) an ascending portion, and (3) an emer vent part. 
Fic. 358.—SECTION THROUGH THE PONS VAROLII OF THE ORANG, 
Showing the nucleus and intrapontine course of the facial nerve. The left side of the drawing is taken 
from a section at a slightly lower level than the section from which the right side is taken. 
A B 
1. Ascending part of facial nerve. 1. Ascending part of facial nerve. 
2. Posterior longitudinal bundle. 2. Emergent portion of facial nerve. 
3. Descending root of eighth nerve. 3. Restiform body. 
4. Radicular fibres of facial nerve. 4. Nucleus of sixth nerve. 
5. Restiform body. 5. Sixth nerve. 
6. Facial nucleus. 6. Emergent part of facial nerve. 
7. Spinal root of fifth nerve. 7. Peduncle of superior olive. 
8. Vestibular nerve. 8. Superior olive. 
9. Superior olive. 9. Corpus tré pe 
10. Fillet. 10. Facial nerve 
11. Pyrainidal tract. 11. Sixth nerve. 
12. Transverse fibres of pons. 12. Pyramidal tract. 
13. Transverse fibres of pons. 
The radicular part of the facial nerve (Fig. 399) 1s composed of a large number 
of fine loosely-arranged bundles of fibres, which issue from the outer and dorsal 
aspect of the nucleus and proceed backwards and slightly inwards through the 
pons. Reaching the floor of the fourth ventricle they curve inwards, and the 
bundles which lie highest up sweep over the outer and dorsal aspect of the lower 
part of the nucleus of the sixth nerve. Close to the mesial plane they turn 
sharply upwards and are collected into a single solid nerve-bundle, which consti- 
tutes the ascending part of the facial nerve > Figs. 358 and 359). This proceeds 
vertically upwards immediately beneath the ependyma of the ventricular floor, on 
the dorsal aspect of the posterior longitudinal bundle, and along the inner side of 
the sixth or abducent nucleus, for a distance of about five millimetres. Suddenly the 
nerve bends outwards at a right angle and curves a second time over the dorsal aspect 
of the sixth or abducent nucleus. The nerve now passes straight to the place of 
exit from the brain, and this part of the intrapontine trunk may be termed the 
