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104 ANATOMY.
The Dented Caned extends through the body of the bone from the
posterior (inferior) dental foramen to the anterior (mental) foramen.
Its course is at first downward and forward, until it reaches the body
of the bone, through which it runs in a horizontal direction, finally
passing forward and opening through the mental foramen on the outer
surface of the bone. It lies beneath the alveolar process, and communi-
cates with the teeth and bony tissue through small canals. Opposite
the mental foramen in the substance of the bone there are small canals
passing forward to the cuspid and incisor teeth and the symphysis of the
chin. The posterior (inferior) dental canal and its branches transmit
the inferior dental nerve, artery, and vein.
The Superior Border of the Reimus.—Arising from this anteriorly is
an elevated process of bone, the coronoid process. From its posterior
portion there arises a rounded eminence of bone, the condyloid process,
which is continuous with the posterior border of the ramus.
Tlie Coronoid Process is flat and pointed, being thinner at the apex
than at the base. The anterior border is a continuation of the external
oblique line. This border bends slightly outward as it ascends, and
terminates in the apex of the process. Extending downward and for-
ward from the apex of this process on its internal surface is a curved
ridge of bone Mhich joins the internal oblique line just posterior to the
wisdom tooth. Between the anterior border and this rounded ridge of
bone, posterior to the third molar tooth, is a wide groove for the inser-
tion of a part of the temporal muscle above and the buccinator muscle
below. The posterior border of this process is thin, and forms the
anterior margin of the sigmoid notch. The outer surface of this process
is smooth, and affords attachment to a portion of the temporal and
masseter muscles. The inner surface is rough, and gives attachment to
the temporal muscle sujieriorly.
The Condyloid Process is shorter, thicker, and more massive than
the coronoid. It is continuous with the posterior or free border of the
ramus. As this border extends upward it widens, until it forms an
articulating surface convex in outline. Tlie superior surface of the
condvloid process articulates with the anterior portion of the glenoid
fossa of the temporal bone. This surface is separated from the glenoid
fossa by interarticular fibro-cartilage.
The Neck is that constricted portion of bone immediately below the
articulating surface. Just internal to the posterior portion of the supe-
rior border of the ramus it presents a depression, the pterygoid fossa, for
the insertion of the greater part of the external pterygoid muscle. At
the junction of the nec^k with tlie articulating surface of the bone
externally is a tubercle for the insertion of the external lateral ligament.
Between the coronoid and condyloid processes is situated the sigmoid
notch. The border of this notch is thin and crossed by tlie masseteric
artery and nerve on their way to the masseter muscle.
The Inferior Border of the ramus is continuous with that of the body
of the l)one. The point of junction l)etwecn the inferior and posterior
borders is the angle. This angle extends outwaixlly, and is grooved
and roughened for the insertion of part of the superficial portion of the
masseter muscle.