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AREOLAR TISSUE, TENDONS, AND MUSCLES. 197 ;

and in the act of sncking constrict the nipple. Each muscle may be
looked upon as a sphincter on a deeper plane than the lips, but like it
in nature, and it is supplied by the same motor nerve—viz. the facial.
It is also a noteworthy fact that the plane of the two muscles limits
the region of involution of the epiblast, so that the palato-glossal mus-
cles are less splanchnic than the pharyngeal muscles proper."
Tlie Palato-Eudachian, or Totsor Falati, is a broad thin muscle
extending from the orifice of the Eustachian tube to the palate, and
having a vertical and a horizontal portion.
TJic Vertical Portion arises from the scaphoid fossa at the root of the
pterygoid plates, the spinous process of the sphenoid bone, and the
lower and outer side of the Eustachian tube. Its flattened belly descends
perpendicularly between the inner side of the internal ])terygoid muscle
and the outer side of the inner pterygoid plate, at the lower portion of
Avhich it becomes a tendon and passes around the hanuilar process, and
continues thence to its insertion, forming the horizontal portion of the
muscle. There is a synovial bursa in connection with the tendon and the
process which allows the tendon to work backward and forward.
The Horizontal Portion passes inward, and is inserted into the apo-
neurosis of the soft palate and transverse ridge on the under surface
of the palate bone.
Relations.—Vertical portion, on its external surface, with the internal
pterygoid muscle ; internal surface with the levator palati muscle.
Horizontal portion, at the point of its insertion into the soft palate
the
the aponeurotic expansion is anterior to the levator palati muscle ;
under surface is covered by mucous membrane.
Neri^es.—The muscle is supplied by branches from the otic ganglion.
Action.—The palato-Eustachian, or tensor palati, has generally been
supposed to make the palate tense, and for this reason severance of the
tendon at the hamular process previous to performing the operation of
staphylorrhaphy Avas frequently favored. The principal function of the
muscle is now considered to be to open the orifice of the Eustachian
tube.
The Levator Palati is a long, thin, round muscle, extending from the
temporal bone to the palate at the lateral borders of the posterior nares.
It arises by a narrow tendon from the under surface of the petrous por-
tion of the temporal bone, anterior to the carotid canal, and from the
hnver margin of the cartilage of the Eustachian tube, thence passing-
downward, inward, and forward into the pharynx over the concave
margin of the superior constrictor, spreading out as it approaches the
soft ])alate, where the anterior and lesser part is inserted into the
aponeurosis of the palate ; the posterior or larger part meets the fibres
from the opposite side underneath the azygos uvulse muscle.
Relations.—Its lateral surface with the tensor palati and superior
constrictor muscles ; the internal surface is covered with mucous mem-
brane.
Actions.—" With reference to the soft palate : the muscle elevates the
soft palate and makes it tense, since the right and left muscles act syn-
chronously. With reference to the Eustachian tube : the shortening of
the body of the muscle, too-ether with the increase of its diameter, has a