Pseudosubluxation Refers to the normal mobility of the cervical vertebrae, IN FLEXION, which may appear pathologic Distinguishing between Pseudosubluxation and Pathologic - The displacement should only occur in flexion (Not extension) (1) most pediatric c-spine films are in flexion due to the relatively larger occiput - Swischuk Line (1) Line that is drawn from anterior aspects of C1 to C3 spinous processes (2) This line should be within 2 mm of the anterior aspect of the C2 spinous process - Spinal-Laminar Line (1) The line drawn connecting the lamina of C1, C2, and C3 should remain intact even in flexion If you suspect that the misalignment represents pseudosubluxation, than you can reposition in extension; if it resolves, it is consistent with pseudosubluxation. But be careful, if mechanism warrants it, obtain CT to r/o hangman s fracture instead. Anterior displacement of C2 in children: physiologic or pathologic. LE Swischuk. Radiology. Vol 122(3) 1977. p 759-763.