ORAL SURG mandible fracture management Flashcards
what are the 2 parts of the condyle?
head
neck
where does the lateral pterygoid attach?
pterygoid fovea
what anatomical structure is behind the external oblique ridge?
ramus of the mandible
what anatomical structure is inferior the the external oblique ridge?
angle of the mandible
what foramen are found in the middle portion of the mandible?
lingual and mental
where does the mylohyoid muscle attach?
oblique line on the lingual surface of mandible
what part of the mandible contains teeth?
alveolar process
where does the mentalis muscle attach?
mental tubercles
what exits through the mental foramen?
terminal branch of the IAN
where is the mental foramen?
between apices of premolars
define a fracture?
a break or a breach in the continuity of normal anatomical structure of a bone by the application of excessive force resulting in 2 or more fragments of the involved bone
why does the mandible often break in more than 1 place?
due to its horseshoe shape
what structure is a known point of weakness?
condylar neck (crumple zone)
what is the aetiology of mandibular fractures?
assault
sporting injury
RTA
pathological
what types of pathology predispose the mandible to fracture?
osteolytic lesions:
cysts
tumours
what are the 5 types of fractures seen in the mandible?
simple
compound
comminuted
greenstick
pathological
define a simple fracture?
undisplaced
overlying periosteum is intact
radiograph shows crack through cortical layer of bone
describe a compound fracture?
perforated through periosteum and often skin
presents externally
involving tooth socket
why do compound fractures predispose mandible to infection?
the fracture line runs through the PDL into the oral cavity, exposing mandible to the oral microbiota
describe a comminuted fracture?
fracture pattern has multiple fracture lines
bone broken to small fragments
describe a greenstick fracture?
uncommon
outer cortices fracture and inner cortex flexes
no displacement
where are the sites in the mandible that can fracture?
dento-alveolar
condylar
coronoid
ramus
angle
body
parasymphysis
symphysis
where is the commonest area of fracture to the mandible?
condylar neck
angle
why is the condyle known as the crumple zone?
instead of driving the condyle into the skull, it will break to prevent damage to the brain
why is the angle of the mandible a point of weakness?
the presence of erupted or partially erupted lower 8s
why is the parasymphysis a point of weakness?
root of the canine
in what direction does the coronoid process usually displace and why?
superiorly due to the temporalis point of attachment
what is the relevance of the muscles attached to the mandible and fractures?
dependent on the pattern of the fracture, the muscles can pull the fracture together or apart causing displacement
causes significant pain
in what way do horizontally favourable fractures pull?
upwards
in what way do vertically favourable fractures pull?
laterally
list the muscles attached to the mandible which may affect the distraction of fracture
medial and lateral pterygoid
temporalis
masseter
digastric
geniohyoid
genioglossus
mylohyoid
what direction does the lateral pterygoid displace a condyle fracture?
anteriorly and medially
what direction does the temporalis, masseter and med. pterygoid displace a proximal segment fracture?
superiorly and medially
what direction does the digastric, geniohyoid, genioglossus and mylohyoid displace the distal segment fracture?
inferiorly and posterior