The =abducent nerve= (N. abducens) emerges from the brain behind the
pons and just external to the pyramid (Fig. 499). It passes forward
across the pons, pierces the dura mater, and accompanies the third and
ophthalmic nerves, below which it emerges through the foramen lacerum
orbitale. In the orbit it divides into two branches; the larger of these
enters the external rectus, the smaller supplies the superior and
external parts of the retractor muscle of the eyeball. Within the
cranium it receives filaments from the carotid plexus of the
sympathetic.
The fibers of the abducent nerve are axones of the large multipolar
cells of the abducent nucleus which is situated beneath the eminentia
teres of the floor of the fourth ventricle. The nucleus lies within
the loop formed by the fibers of origin of the facial nerve. It is
connected with (_a_) the anterior olive; (_b_) the oculomotor nucleus
of the opposite side; (_c_) the motor area of the cerebral cortex by
means of the pyramidal tract of the opposite side.