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THE NERVOrS SYSTEM. — 295

The Branches to tlie External Auditory Meatus are two in number,
superior and inferior. They pass between the bone and the eartihige to
enter the meatus, and are distributed to the lining of the ear. The
superior branch gives oif a filament to the membrana tympani.
The Parotid Branches supply the parotid gland. They are frequently
eonneeted Avith the facial nerve.
The Anterior Auricular Branches are usually two in number. They
pass between the tragus and helix, and are distributed to the concave
-surface of the auricle.

The Lingual Nerve..
The lingual or gustatory nerve is second in size, and an important
branch of the third division of the fifth. From its origin it passes
down on the internal surface of the external pterygoid muscle, anterior
and a little to the inner side of the inferior dental nerve. These two
nerves have been obsers'ed arising from a common trunk and bifurcat-
ing near the posterior dental foramen. As the lingual nerve reaches
the hnver border of the external pterygoid muscle it curves forward
between the internal ptervgcjid muscle and the ramus of the lower jaw,
inclines inward over the superior constrictor of the pharynx, under the
^tylo-glossus muscle and above the deep portion of the submaxillary
muco-salivarv gland. It then extends forward, crosses Wharton's duct,
passes below the mucous membrane of the alveolar lingual groove, and
terminates at the apex of the tongue.
Branches of Communication.—^ear the origin of the lingual nerve a
communicating branch passes over the internal maxillary artery to the
inferior dental nerve. There is also a small branch which passes to
the hypoglossal nerve. This nerve also forms a plexus, from which
branches are distributed to the walls of the internal jugular vein, a
portion of the sinuses and the cancelli of the occipital l)one, and inter-
lace with branches which pass through the anterior condyloid foramen.
The chorda tympani branch, which is a small ner\'e, arises from the
facial, and descends from the proximal extremity of the squamoso-
lympanic suture (fissure of Glasserius) to the acute angle of the lingual
nerve as it passes forward close to the lower border of the external
pterygoid muscle. At first there is only a mechanical union between
these two nerves, but subsequently they are intimately associated.
Branches pass directly to the submaxillary ganglion where it is in close
relation with the submaxillary muco-salivarv gland. Anterior to the
last branch, one or two communicating filaments descend over the first
portion of the hypoglossal muscle to interlace with filaments from the
hypoglossal nerve.
The branches of distribution of the lingual nerve are
A small branch to the palato-glossal fold (anterior palatine arch) and
the tonsils.
A sublingual branch, which is distributed to the mucous membrane
of the floor of the mouth, the gum tissue on the inner surface of the
inferior maxillary bone, and the sublingual mucftus gland.
The lingual or termimd branches, which passs upward between the