Image DDX




Case of the Week 248

What's the most likely diagnosis?

  • 38 year-old in a motor vehicle accident

  1. Jefferson Fracture
  2. Hangman's Fracture
  3. Fracture of the Dens
  4. Burst Fracture
  5. Clay Shoveler's Fracture



3. Fracture of the Dens



More (Click Discussion Tab)

Fracture of the Dens

General considerations

  • Most dens fractures are caused by motor vehicle accidents and falls
  • About 1/3 of C-spine injuries occur at C2 and about ½ at C6-C7
  • As expected, most fatal cervical spine injuries occur at C1 or C2
  • Most odontoid fractures occur with flexion, extension and rotation

Normal anatomy

  • Odontoid process (dens) of C2 (atlas) articulates with C1 (axis) with three joints
    • Central atlantoaxial joint
    • Bilateral. Lateral atlantoaxial joints
  • Ligaments (transverse and dentate) provide rotational and translational stability
    • Transverse ligament holds dens in close approximation to anterior arch of C1
  • Dens represents the fused remnants of the body of C1


More ...

New Format

  • New, easier to use format
  • All navigational items can be found in the drop-down menu at top of each page
  • Best viewed with Javascript enabled, IE6 or later

Available Now

  • Just the knowledge you need to know
  • For clinical rotations, USMLEs, radiologic technology
  • Bonus access to for more interactive quizzes, anatomy exercises, full text
  • Click the book cover for more information is an award-winning educational site aimed primarily at medical students and radiology residents-in-training, containing  lectures, handouts, images, Cases of the Week, archives of case quizzes, flashcards of differential diagnoses and “most commons” lists, primarily in the areas of chest, GI, cardiac, and bone radiology.