Diagnosis

Complex fractures of the symphysis and parasymphysis

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 Imaging
 Basal triangle (wedge) fracture
 Mechanism of the injury
Imaging
Complex fractures of the symphysis and parasymphysis

Routine diagnosis of mandibular fractures should include radiographs taken in two planes at 90° to each other.

In comminuted fractures CT and/or digital volume tomography (DVT) are extremely useful for adequate three-dimensional preoperative assessment of the fracture pattern, segmentation and fragment displacement.

Axial CT view of a comminuted symphyseal fracture.


Complex fractures of the symphysis and parasymphysis

Coronal CT view of the same case.


Complex fractures of the symphysis and parasymphysis

3-D reconstructions of comminuted fractures are also useful in understanding the fracture morphology.


Complex fractures of the symphysis and parasymphysis

3-D reconstruction of the same case.


Complex fractures of the symphysis and parasymphysis

Clinical photograph of the same case.


Basal triangle (wedge) fracture
Complex fractures of the symphysis and parasymphysis

Mandibular symphyseal fractures involving the basal triangle represent a special severity grade. This type of fracture can be classified at the lower end of the scale of complex fractures.


Complex fractures of the symphysis and parasymphysis

Panoramic x-ray showing large triangular basal fracture of the symphysis.


Complex fractures of the symphysis and parasymphysis

Clinical photograph of the same case.


Mechanism of the injury
Complex fractures of the symphysis and parasymphysis

Most often this more severe type of mandibular symphyseal fracture results from heavy impact during physical altercation or in traffic accidents.

Basal triangle fractures
The vector of the impact has a diagonal superior-inferior direction causing compressive forces at the lower mandibular border leading to a blowout of a bony triangle. The base of the bony triangle lies along the lower mandibular border and its apex reaches the alveolar process in this particular fracture mechanism.

Symphyseal triangular fractures are rare in comparison to simple fractures.