120 
section so as to lie wedged in between the axis of the brain 
and the optic lobe. It at once turns sharply downwards 
and forwards, and becomes closely opposed to the dorsum 
of the oculomotorius. For some sections the two nerves 
can be distinguished, but in front they appear to fuse 
completely, and cannot be distinguished even under the 
high power. The pathetic is, however, given off again 
from the dorsum of the oculomotor, passes forwards and 
downwards, pierces the membranous wall of the brain case 
obliquely in front, and breaks up in the superior oblique 
muscle of the eye as shown in the figure. 
On the left side the relations of the nerve to the brain 
and for some distance in front are essentially the same as 
on the right side. As, however, it approaches the eyes 
(section 392 of chart), it begins to pass towards the lower 
or right optic nerve. Subsequently it takes up a position 
above and to the left of the upper or left optic nerve, 
having now crossed over the top of the parasphenoid and 
lying distinctly to the right of the morphological middle 
line. The two optic nerves having dipped down the left 
pathetic crosses over the left optic to its right side. The 
left optic now turns upwards towards its eye, so that the 
left pathetic hes considerably below it. The latter after- 
wards passes upwards to the left side of the frontal bridge, 
and is seen below the right pathetic. It finally breaks 
up in the left superior oblique in much the same way as 
the right. 
Nervus abducens—Vl. 
The sixth nerve (vi. 7.e.), which consists mostly of 
large well myelinated fibres together with some small 
ones, arises from the medulla by two small rootlets some 
distance from the middle line. Both these rootlets have 
apparently a common nucleus situated far from the middle 
