An odontoid fracture involves a fracture of which cervical structure?

• A. Body of C2
• B. Spinous process of C2
• C. Dens (odontoid process) of C2
• D. Pars interarticularis of C2

Answer: (C)

This question hinges on identifying the specific structure that forms the pivot for head rotation. An odontoid fracture means the dens, the tooth-like projection that rises from the top of the C2 vertebral body, is fractured. The dens (odontoid process) sits in front of the spinal cord and acts as the pivot around which the atlas (C1) rotates, with the transverse ligament keeping it aligned within the ring of C1–C2.

If the fracture involved the body of C2, or the spinous process, or the pars interarticularis, we’d be describing injuries to those separate parts—vertebral body fracture, a posterior element fracture, or a Hangman-type fracture, respectively. But for an odontoid fracture, the key structure affected is the dens itself.