The Anatomy, Physiology, Pathology, and Remedial Treatment of the Fifth Pair of Nerves. [Volume: 2, Issue: 2, September, 1860, pp. 77-88]

THE FIFTH PAIR OF NERVES.

83

The posterior root has its origin, or, physiologically speaking, its termination, in the lateral tract of the medulla oblongata, immediately behind
the olivary body, and is composed of thirty or forty fasciculi, which are
divisible into a hundred filaments. Tracing the root from its point of
termination outward, it is found to ascend to the pons varioli, pass between its fibres, and then emerge from it in a filamentous trunk, where the
pons joins the crus cerebelli; it then passes forward and expands into the
large semilunar ganglion of Gasser, which rests in a depression on the
upper surface of the petrous portion of the temporal bone. From the ganglion of Gasser three large trunks arise, of which the first or ophthalmic
passes out of the skull through the sphenoidal fissure, the second or superior maxillary through the foramen rotundum, and the third or inferior
maxillary through the foramen ovale.
Turning to the anterior or motor root of the fifth, it is found to consist
of a very few fasciculi, which arise from the pyramidal body of tie medulla
oblongata, and pass through the pons varioli close to the sensory root,
without, however, any union taking place between the fasciculi of the two
roots. After emerging from the pons, the motor root passes under the
sensory root and the ganglion of Gasser, and escapes from the skull through
the foramen ovale, where it unites with the inferior maxillary branch just
beyond the otic ganglion.
Proceeding now to trace the course of the three branches given off
from the ganglion of Gasser, the first presented is the
OPHTHALMIC NERVE.
The Ophthalmic Nerve, which comes off from the upper angle of the
ganglion, is about an inch in length, somewhat flattened, and runs in the
direction of tile sphenoidal fissure, through which it passes to the orbit,
where it divides into three branches: the frontal, laclirymal, and nasal.
The Frontal Nerve, the largest branch of the ophthalmic, passes
forward for some distance along the upper part of the orbit, and then
divides into the supra-orbital and supra-trochlear, the first escaping from
the orbit by the supra-orbital foramen, the second passing to the angle of
the orbit. They are distributed to the integument of the forehead, upper
eyelid, and the conjunctiva.
The. Lachrymal Nerve, the smallest division of the ophthalmic, proceeds along the external part of the orbit to the lachrymal gland, where
it divides into a superior and inferior branch, which are distributed to
the upper and under surface of the gland, upper lid, and outer angle of
the eye; the superior branch, in addition, anastomosing with the facial
nerve.
The Nasal Nerve crosses the optic nerve and leaves the orbit by
the anterior ethmoidal foramen, and then passes through the slit-like
opening by the side of the crista gala of the ethmoid bone, and descends