3. mandible fractures

Dr. Simon Rock
12/28/2020Dr.Simon Rock

 CNV3, the mandibular n., through the foramen ovale
 Inferior alveolar n. through the mandibular foramen
 Inferior dental plexus
 Mental n. through the mental foramen
Arterial Supply
Endosteal blood supply
 Inferior alveolar artery
 Mental artery
Periosteal blood supply (old age)

Jaw Elevators
 Masseter: Arises from zygoma and inserts into the angle and
ramus
 Temporalis: Arises from the infratemporal fossa and inserts
onto the coronoid and ramus
 Medial pterygoid: Arises from medial pterygoid plate and
pyramidal process and inserts into lower mandible
Jaw Depressors
 Lateral pterygoid: lateral pterygoid plate to condylar neck
and TMJ capsule
 Mylohyoid: mylohyoid line to body of hyoid
 Digastric: mastoid notch to the digastric fossa
 Geniohyoid: inferior genial tubercle to anterior hyoid bone

 Mandible most common after nasal fractures
 Mandible : Zygoma : Maxilla 6:2:1
 Ellis 4711 facial fractures, 45% with mandible fractures
 Assault>MVA>Fall>Sports
 Males > females; 3 to 1
 Most prevalent age range: 16-30 year old
 Concomitant injuries are common
 Must rule out spinal injuries
 Dental injuries are commonly associated with other facial
fractures

 Sites of weakness
 Third molar (esp. impacted)
 Socket of canine tooth
 Condylar neck
 Boole et al ( 5196 fractures)
 Young military men
 Angle 35%, Symphysis 20%, Body 12%, Condylar 9%, Subcondylar 4%,
Ramus 4%, Alveolar 3%, Coronoid 1%
 70% 1 fracture, 30% 2 fractures, .2% more than 2
 Facial lacerations 30%, other facial fracture 16%, C-spine 0.8%

Simple or closed
fracture
Compound or open
fracture
Comminuted fracture
Greenstick fracture
Pathologic fracture
Favorable vs
Unfavorable fracture
12/28/2020 Dr.Simon Rock

. According to the severity of the injury
Simple fracture: In which the soft tissue, that may
be damaged, but there is no open wound
communicating the fracture fragment with the
outside.
Compound fracture: In which there is an open
wound with direct communication of the fragments
with the out side.(all body # are compound because
are open in PDL)
.According to the type of fracture
Green stick fracture: There is incomplete
discontinuity of the bone occurs in children.
Complex fracture: In which the fracture occurs in
more than one bone.
Comminuted fracture: In which the bone is fractured
into many fragments.
Pathological # 12/28/2020Dr.Simon Rock

Unilateral fracture: Usually single, but occasional
more than one fracture line may be present in one
side.
Bilateral fracture: Usually occur from
combination of direct and indirect force, e.g. angle
and opposite condylar fracture.
Multiple fracture: Also occurs from the direct
indirect force combination, e.g. symphyseal and
bilateral condylar fracture(parade fracture)

Acording to the cause
Direct force: A direct blow to the mandible is
the most common cause of mandibular
fracture.
Indirect force: Fracture may occur from a blow
applied at a distance from the fracture site,
e.g. a blow to the symphysis may cause
subcondylar fracture.
Excessive muscular contraction: This may
cause fracture as with electric shock therapy,
(Coronoid #)

Condylar process
Coronoid
Ramus
Angle
Body
Symphysis or
Parasymphysis
Alveolar process

. According to the direction of the fracture line
 The fracture line may be horizontal or vertical, each may be
favorable or unfavorable.
 In Angle area Masseter, Medial and Lateral Pterygoid, and
Temporalis tend to draw fractures medial and superior
 Medial Pterygoid is the stronger component
 This Is afected by the vertical or horizontal direction of
fracture line

 Unfavorable Fractures where the muscles tend to draw
fragments apart
 Most angle fractures are horizontally unfavorable
 Most parasymphyseal fractures are vertically unfavorable
 Symphyseal # are favorable why?

 Stabilization via ATLS protocol
 Part of secondary survey
 Blow to face favors parasymphyseal fracture and contralateral
angle fracture
 Fall to chin (bilateral condylar fractures)
 Previous occlusion (Class I-III) ( photos)
 Psychiatric, seizure disorders
 Previous facial trauma
 Other injuries (c-spine, intra-abdominal, likely prolonged
intubation)

Common symptoms of mandibular fracture
 Pain: Especially with motion,
 Tenderness: Palpation over the fracture site reveals tenderness.
 Disability: The patient is unable to open the mouth normally.
 Swelling: Swelling early after injury is due to escape of blood at the
fracture site.
 Discoloration: The overlying tissue become red, bluish or purplish as a
result of hemorrhage or haematoma formation.
 Deformity: Displacement of the fractured fragment may be suggested
by asymmetry of the face and deformity.
Abnormal mobility: The mandible will move in an abnormal way.

Crepitation: The patient may note a greeting,
cracking or griding sound during movement as
the fragments move in contact with each other.
Salivation: Pain and tenderness stimulate
salivary secretion. Drooling of saliva from the
mouth is increased by the inability to swallow the
excessive saliva.
Bad odor: The patient may have offensive breath
due to putrefaction of blood clots and mucous.
Extensive comminution or bilateral fracture of
the symphyseal region may result in sever
respiratory difficulties due to the posterior
displacement of the fractured fragments

Signs Of Mandibular Fracture
 Step defects occlusion
 Palpable step the inferior border
 Tenderness to palpation
 Malocclusion
Trismus (35 mm or less)
 Altered sensation of V3
 Crepitus
 Unnatural mobility
 Ecchymosis in floor of mouth (pathognomonic)
 Mucosal lacerations

 Anesthesia of lower lip is “pathognomonic” of a fracture distal
to the mandibular foramen (degree displacement)
 The converse is not true: not all fractures distal to the
mandibular foramen have mental n. anesthesia
 Dental Exam
 Lost, fractured, or unstable teeth
 Dental Health
 Relation to fracture
 Quantity

Sublingual ecchymosis Step defects, ridge
discontinuity, malocclusion

Malocclusion
Step defects in the
occlusion
Mucosal laceration
Step defects in the
occlusion

 PALPATION
 “Step” Defect
 Unnatural mobility
 Crepitus
 Bony segments
 Subcutaneous emphysema
 Mobility

 Contusion
-Damage to the joint soft tissues leads to
Synovial effusion, haemarthrosis
-Symptoms are pain, limitation of mouth openning and tenderness
over the joint
- Accurate Dx need MRI
- ttt soft diet, analgesics
 Dislocation
Displacement of the condyle from the glenoid foosa(see TMJ topics)
 Fracture

Classification
I According to the extend of the fracture line
A. Intracpsular fracture
Fracture through the condylar head generally
intracpsular.
B. Extracapsular fracture
Fracture line extends through the neck of the
condyle.
C. Subcondylar fracture;
The fracture line runs from the sigmoid notch,
downwards and posteriorly to the posterior border of
the ramus

II. According to the position of the condylar
fragment
A. Undisplaced fracture
The fracture is complete but the fragments remain
in their anatomical positions.
B. Displaced fracture
The condylar head is displaced, medially and
anteriorly but remains within the limits of the
glenoid fossa
C. Dislocated fracture
The condylar head is expelled from the fossa and
out of the limits of the temporomandibular joint.

Unilateral fractures of Condyle
Decreased translational movement, and
functional height of condyle ,lead to
 Deviation of chin toward the fractured side,
 open bite on the opposite side of fracture
Bilateral fractures of condyle
- Anterior open bite
- Gaging of posterior teeth

x-ray (image areas of concern with 2 films at
90o to one another: eg. peri-apicals & 90o
occlusal )
gaps
overlap
lost teeth
displaced teeth
foreign bodies
chest x-ray to locate missing pieces

Radiographs:
 Panoral tomogram: the best single overall view of the mandible (if not
available RL oblique lateral é rotated PA)
 PA mandible: to show medial or lateral displacement of fractured
body angle. not suitable for TMJ
 Reverse townes projection: for TMJ #
 intra-oral
- Periapicals to show position& condition of teeth involved in # line
 - Occlosal views midline # with minimal displacement
 CT scan
 Not as diagnostic as plain films for non displaced fractures of mandible.
 Most useful for coronoid and condylar fractures, associated midface
fractures
-3D CT very useful for condylar #

R
Fractures of mandibular
symphysis and left condyle.

Pathologic fracture associated with
large radicular cyst (lateral-oblique view).
L

R
Mandibular fracture at angle on right
side (PA view).Note the displacement

Alveolar fracture
combined with
fracture through
symphysis:
Standard
occlusal
projection.

 Mandibular fractures are common
 Should managed as early as possible
 Avoid possible infection
 Use the possible available means
 THANK YOU

3. mandible fractures

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