Authors of section

Authors

Ricardo Cienfuegos, Carl-Peter Cornelius, Edward Ellis III, George Kushner

Executive Editors

Marcelo Figari, Gregorio Sánchez Aniceto

General Editor

Daniel Buchbinder

Open all credits

Symphysis and parasymphysis, complex

Imaging

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.

Complex fractures of the symphysis and parasymphysis

Basal triangle (wedge) fracture

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.

Complex fractures of the symphysis and parasymphysis

Mechanism of the injury

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.

Complex fractures of the symphysis and parasymphysis