Six descriptors are commonly used to describe and categorize them:
2. Complete versus incomplete
3. Fracture morphology
4. Open/compound versus closed/noncompound
5. Displaced versus nondisplaced
6. Mobile versus nonmobile
Most clinicians generally subdivide the mandible into the following anatomic locations:
- Symphysis and parasymphysis
- Angle and ramus
- Condylar process and head
- Coronoid process
- Alveolar process
Multiple fractures are those involving more than one anatomical location of the mandible.
Complete versus incomplete
Fractures of the mandible in adults are usually complete so that they interrupt entirely the continuity of the mandibular arch. Such fractures are usually mobile and have various degree of displacement.
On the other hand, incomplete fractures do not extend through both the buccal and the lingual cortices as well as the alveolar and basal borders. This occasionally occurs in adults but more often in children. In such cases, the fracture will be nondisplaced and nonmobile. The incomplete fracture might not therefore require surgical treatment and may be managed only by soft diet.
The fracture morphology refers to the type of fragmentation (number of fragments and fracture lines) and the displacement.
Fractures fall into one of two categories:
Simple fractures are linear (one fracture line) resulting in two fragments.
Complex fractures involve at least two fracture lines and three or more fragments. Complex fractures include:
- Basal triangle (wedge) fractures
- Segmental fractures
- Comminuted fractures
- Defect fractures
Basal triangle (wedge) fracture
A basal wedge fracture involves a triangle of bone at the inferior border.
Segmental fractures present two fracture lines, both being complete, within the same anatomic location.
Comminuted fractures involve multiple fracture lines in the same anatomic location resulting in multiple fragments of bone. The bone is often shattered in the area of fracture, with fracture lines running in three dimensions.
Many clinicians consider comminuted fractures as synonymous with multifragmentary fractures.
Defect fractures are characterized by a loss of bony structure at the fracture site.
Open or closed
Intraoral and facial soft tissues adjacent to a fracture can be involved in the injury.
When the fracture site communicates either intraorally through the mucosa or periodontal ligament, or extraorally through a laceration or avulsive injury of the overlying skin, the fracture is considered as open. Therefore all fractures involving the tooth-bearing areas of the jaws are considered as open fractures.
The terms open fractures and compound fractures are synonymous.
The soft tissues (intra and extraoral) adjacent to a closed fracture are intact.
Fractures can be considered displaced or nondisplaced depending on the relationship of the fracture ends. A fracture is displaced if the fragments are not perfectly anatomically aligned. Displacement is grossly graded as minimal, moderate and severe. Nevertheless, there is no universally accepted definition for these terms.
The importance of “displacement” is that the more displaced the fracture, the more likely it is to be mobile and contaminated when open.
The terms dislocated, subluxated, and luxated are used to describe the abnormal relationship of the articular surfaces of the condyle and glenoid fossa to one another. These terms are synonymous. Some surgeons consider them a subcategory of displacement.
Mobile versus nonmobile
The first five fracture characteristics can all be gleaned from the x-rays. The sixth characteristic, fracture mobility, can be inferred in many cases from the x-rays when there is displacement, but is really a clinical descriptor that requires the clinician to use both hands, one on either side of the fracture, to feel for mobility.
Mobile fractures are more painful to the patient because any movement of the mandible such as in speaking, eating or swallowing creates discomfort.