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196 ANATOMY.

terior portion^ which embrace the levator palati and the azygos uvulae
muscles.
The Anterior Head or Portion is the thickest ; the fibres at the com-
mencement near the median line of tlie palate are associated with those
of the opposite side ; they pass outward between the levator and tensor
palati nuiscles ; fibres are also received from the free edge of the hard
palate and the aponeurosis of the velum.
The Posterior Head or Portion consists of scattered fibres, commen-
cing in the median line and associating with those of the opposite side.
At the edge of tlie soft palate the two portions unite, and receive two
slender bundles which arise from tlie inferior and anterior part of the
Eustachian tube (salpingo-pharyngeus, Santorini) ; from this it passes
it spreads
outward, downward, and backward posteriorly to the tonsils ;
out, joining the fibres of the stylo-pharyngeus muscle, and is inserted
mainly into the superior and posterior border of the thyroid cartilage.
The remainder of its fibres are received into the fibrous layer of the
inferior part of the pharynx, passing as far as, or crossing, the median
line, and interlacing with those of the opposite side.
This muscle and the mucous membrane covering it form the palato-
pharyngeal fold, or " posterior half arch."
Relations.—At its origin the soft palate. Its anterior and posterior
surfaces are covered by mucous membrane, a layer of palatine glands
resting between the membrane and the muscle. Its superior surtace is
related with the levator palati muscle. In the pharynx it passes between
the mucous membrane and the constrictor muscles.
Nerves.—Branches of nerves from Meckel's ganglion (spheno-pala-
tine).
Action.—To elevate the pharynx in deglutition, the palate having
first been elevated by the levator palati. In its action it assumes a
nearly vertical position in the posterior part of the pharynx. Allen ^ and
Yule^ conclude from observation that the palato-pharvngeus is the chief
factor in opening the Eustachian tube ; it also keeps the soft palate in
position during respiration.
The Palato-glossus is a small muscle extending from the soft palate
it is narrower in the middle than
to the posterior part of the tongue ;
at its origin or insertion, and arises from the under surface of the soft
palate neal' the base of the uvula, the fibres of each side interlacing
at their origins. It passes downward, forward, and outward along
the lateral wall of the pharynx, anterior to the tonsils, and is inserted,
with the stylo-glossus, into the side and base of the tongue. This
muscle and the mucous membrane covering it form the palato-glossus
fold, or " anterior half ai'ch."
Relcdions.—It passes downward along the outer wall of the pharynx,
between the constrictors and the mucous membrane.
Nerves.—Branches of the facial.
Action.—To depress and draw slightly forward the palate and assist
in elevating and drawing back the tongue. Allen ^ observes : "Both
muscles, acting together, depress the soft palate and dra^v' it forward,
^ Allen's "Memoir on Soft Palate," Tmn^. Amer. ^fe(l. AKsnr., 1872, p. 537.
2 Joicrnal of Anut. and P/iys.. viii., 1873. •* Allen's Human Anatomu, p. 259.