Book contents
- Frontmatter
- Contents
- List of contributors
- Preface
- Acknowledgments
- Section 1 Brain, head, and neck
- Section 2 Spine
- Case 19 Variants of the upper cervical spine
- Case 20 Atlantoaxial rotatory fixation versus head rotation
- Case 21 Cervical flexion and extension radiographs after blunt trauma
- Case 22 Pseudosubluxation of C2–C3
- Case 23 Calcific tendinitis of the longus colli
- Case 24 Motion artifact simulating spinal fracture
- Case 25 Pars interarticularis defects
- Case 26 Limbus vertebra
- Case 27 Transitional vertebrae
- Case 28 Subtle injuries in ankylotic spine disorders
- Case 29 Spinal dural arteriovenous fistula
- Section 3 Thorax
- Section 4 Cardiovascular
- Section 5 Abdomen
- Section 6 Pelvis
- Section 7 Musculoskeletal
- Section 8 Pediatrics
- Index
- References
Case 19 - Variants of the upper cervical spine
from Section 2 - Spine
Published online by Cambridge University Press: 05 March 2013
- Frontmatter
- Contents
- List of contributors
- Preface
- Acknowledgments
- Section 1 Brain, head, and neck
- Section 2 Spine
- Case 19 Variants of the upper cervical spine
- Case 20 Atlantoaxial rotatory fixation versus head rotation
- Case 21 Cervical flexion and extension radiographs after blunt trauma
- Case 22 Pseudosubluxation of C2–C3
- Case 23 Calcific tendinitis of the longus colli
- Case 24 Motion artifact simulating spinal fracture
- Case 25 Pars interarticularis defects
- Case 26 Limbus vertebra
- Case 27 Transitional vertebrae
- Case 28 Subtle injuries in ankylotic spine disorders
- Case 29 Spinal dural arteriovenous fistula
- Section 3 Thorax
- Section 4 Cardiovascular
- Section 5 Abdomen
- Section 6 Pelvis
- Section 7 Musculoskeletal
- Section 8 Pediatrics
- Index
- References
Summary
Imaging description
There are several skeletal variants of the C1 and C2 vertebrae which may be confused with injury. Knowledge of the normal development of these vertebrae is essential for distinguishing anatomic variants from pathology.
The atlas typically develops from three primary ossification centers: one anterior arch and two neural arches. Two neurocentral synchondroses separate the anterior arch from the neural arches (Figure 19.1). A single posterior synchondrosis separates the neural arches. The atlas is normally fused by eight years of age [1].
The axis typically develops from five primary ossification centers: two odontoid centers, two neural arches, and one centrum. The odontoid centers usually fuse prior to birth (Figure 19.2). The remaining primary centers are usually fused by six years of age. A secondary center of ossification, known as the os terminale, forms at the odontoid tip and usually fuses by 12 years of age [2].
Incomplete fusion of the atlas may result in a cleft, usually at the site of a synchondrosis. The cleft will usually demonstrate a smooth margin at a characteristic location, and should not be mistaken for a fracture (Figure 19.3). If there is non-development of the anterior arch, the neural arches may overgrow and attempt to fuse anteriorly, resulting in an anterior midline cleft (Figure 19.4).
- Type
- Chapter
- Information
- Pearls and Pitfalls in Emergency RadiologyVariants and Other Difficult Diagnoses, pp. 69 - 71Publisher: Cambridge University PressPrint publication year: 2013