Fig. 5

Condylus tertius: a sagittal reformatted CT image through the craniocervical junction of a 54-year-old male cyclist who fell of his bicycle at speed sustaining facial fractures. The condylus tertius of unfused hypochordal bow is demonstrated (thick arrow) and is an important mimic of fracture at the basion. Note the depressed comminuted facial fractures involving the frontal sinus and nasal bone (thin arrows); b axial CT image of the same patient demonstrates the unfused bone remnant at the left side of the basion (arrow), not to be mistaken for a displaced fracture fragment