mandible

1. The MandibleBone

2. Is the only movable bone of the skull
It has a horizontal-shaped body and
two almost vertical rami

3.  Mandibular body has two surfaces (external
and internal) and two borders (superior and
inferior)

4. EXTERNAL SURFACE ( ANTERIOR SURFACE)
Displays in the midline a faint ridge, often absent,
marking the site of mental symphysis, the line of
fusion of the two halves of fetal bone.
Inferiorly, the ridge encloses a triangular
eminence, the mental protuberance
Often, the base of the protuberance is centrally
depressed but elevated on each side of it as a
mental tubercle.

5.  On each side of the median ridge and below the incisor teeth
lies the incisive fossa of the mandible, giving attachement to
mentalis and incisivus labii inferioris muscles
 Behind the fossa, the canine eminence of the mandible
overlies the root of canine tooth
 Midway between upper and lower borders of the mandibular
body, in line with the second premolar tooth ( sometimes in
line with the interval between premolars), lies the mental
foramen transmitting the mental vessels and nerve

6.  The mental foramen is the anterior opening of
the mandibular canal ( inferior alveolar canal)
and is directed bacward, lateralward and upward
 Laterally, the external surface is crossed by the
oblique line, which extends backward and
upward from below the mental foramen to the
anterior border of the ramus
 Anterior part of the oblique line provides
attachement to depressor labii inferioris and
depressor anguli oris, posterior part of the line
serves as attachement for buccinator.
 To the area below the oblique line the platysma
is attached

7.  INTERNAL SURFACE (POSTERIOR
SURFACE)
 Displays in the midline a faint ridge, marking
the site of mental symphysis.
 Inferiorly, the ridge is elevated by the usually
paired upper and lower mental spines (genial
tubercles)
 The superior mental spine affords attachement
to genioglossus, the inferior mental spine to the
geniohyioid
 On each side of the median ridge, the internal
surface is divided by the oblique mylohyoid line,
extending upward and backward from below the
mental spines to a little below the back of the
third molar tooth.

8.  To the mylohyoid line is attached the mylohyoid muscle,
close to the posterior end of the line the superior
pharyngeal constrictor takes the origin above superior
constrictor and behind the third molar the
pterygomandibular raphe is attached.
 Between the third molar and posterior end of mylohyoid
line, the lingual nerve comes in close contact with bone,
often in a shallow groove

9.  The mylohyoid line divides each half of the
internal surface into an upper sublingual
fossa accomodating the sublingual gland,
and lower submandibular fossa lodging the
superficial part of submandibular gland
 The posterior part of submandibular fossa
displays the mylohyoid groove, extending
from the inner aspect of the ramus and
containing the corresponding vessels and
nerve
 Sometimes, above the mylohyoid line and
medial to the roots of molar teeth, a bony
projection may arise, termed mandibular
torus

10. Superior border (alveolar
process)
Displays sixteen sockets, the
alveoli, for the roots of
mandibular teeth
Between the alveoli are
interalveolar (interdental)
septa
Inferior border (base)
Displays, on each side of the
midline, a digastric fossa, for
the origins of the anterior
belly of digastric.
At the point where is
continues with the lower
border of the ramus, a groove
transmitting the facial artery
is often present, termed the
premasseteric notch

11.  MANDIBULAR RAMUS
 Has two surfaces ( lateral and medial) and four borders
( anterior, posterior, superior and inferior)

12.  LATERAL SURFACE (EXTERNAL SURFACE)
 Has oblique ridges toward the mandibular angle, collectively
names masseteric tuberosity
 The lateral surface affords attachement to masseter, except
posterosuperiorly where is overlapped by the parotid gland

13.  MEDIAL SURFACE (INTERNAL SURFACE)
 The mandibular foramen leading into the
mandibular canal and giving passage to the
inferior alveolar vessels and nerve
 Anteromedially, the foramen is guarded by an
upward tongue-like spine, the lingula, serving
as attachment for the sphenomandibular
ligament
 From behind the lingula, the mylohyoid groove
runs downward and forward into mandibular
body
 The medial surface of ramus has oblique ridges
toward the mandibular angle, named pterygoid
tuberosity, which provides attachement to
medial pterygoid

14.  Descending from the tip of coronoid process is a ridge, the
temporal crest, which reaches the back of the third molar
 The triangular depression bounded medially by the
temporal crest and laterally by the anterior border of the
ramus is called retromolar fossa
 The lowest part of the retromolar fossa provides attachment
to the posterior fibers of the buccinator, the upper part
receives the attachment of temporalis

15.  POSTERIOR BORDER
 Is thick and rounded, and relates
to the parotid gland
 ANTERIOR BORDER
 Is continuous above with the
anterior border of coronoid process
and below with the oblique line of
mandibular body
 It gives insertion to temporalis

16.  SUPERIOR BORDER displays two process
bounding the mandibular notch, the
coronoid process in front, and condylar
process behind
 The mandbular notch gives passage to the
masseteric vessels and nerve
 The coronoid process is a triangular upward
projection, its anterior border is continous
below into anterior ramal border, its
posterior border forms the anterior
boundary of the mandibular notch, its
lateral surface is flat, its medial surface is
marked by a descending idge, temporal crest

17.  The coronoid process serves as attachment for temporalis, which involves
both borders, apex and the entire medial surface
 The condylar process consist of two parts, the mandibular head and neck
 Mandibular condyle articulates with the mandibular fossa of temporal
bone by an articular disc

18.  The mandibular neck has four surfaces,
the lateral and posterior surfaces receive
the attachment of temporomandibular
ligament, medial surface is related to
auriculotemporal nerve, the anterior
srface bears a depression, the pterygoid
fovea
 The edge between anterior and lateral
neck surfaces forms the posterior
boundary of mandibular notch
 The pterygoid fovea affords attachment
to lateral pterygoid muscle

19. INFERIOR BORDER is continous in
front with the mandibular base, behind
it meets the posterior border at the angle
The mandibular angle is typically
everted in males and inverted in females
On each side, the angle is marked by the
oblique ridges, constituting the
masseteric and pterygoid tuberosities.
Between the two tuberosities the
stylomandibular ligament is attached

20.  MANDIBULAR CANAL
 Begins at the mandibular foramen and
runs downward and forward within
mandibular ramus, then forward within
mandibular body and below the alveoli of
molar teeth
 Below the interval between the premolar
teeth, the canal divides into mental and
incisive canals
 The mandibular canal (inferior alveolar
canal) transmits the inferior alveolar
vessels and nerve

21. MANDIBULAR
FRACTURES