Cervical Vertebrae (C1–C7)¶
Definition¶
The cervical spine comprises the uppermost seven vertebrae of the vertebral column, extending from the base of the skull to the cervicothoracic junction. It is the most mobile segment of the spine and houses the cervical spinal cord, vertebral arteries, and exiting cervical nerve roots. The cervical spine is subdivided into the upper cervical spine (occiput–C2) and the subaxial cervical spine (C3–C7).
Anatomy¶
General Features of Cervical Vertebrae¶
Cervical vertebrae are the smallest of the mobile vertebrae and share several distinguishing features:
- Small, wide vertebral bodies — wider in the transverse dimension than AP
- Uncinate processes — bony lips on the posterolateral margins of C3–C7 vertebral bodies forming the uncovertebral (Luschka) joints
- Bifid spinous processes — typically seen at C3–C5; C7 has a long, non-bifid "vertebra prominens"
- Transverse foramina — bilateral openings in the transverse processes transmitting the vertebral arteries (C1–C6)
- Triangular vertebral foramen — larger than thoracic or lumbar to accommodate the cervical enlargement of the spinal cord
Unique Vertebrae¶
The first two cervical vertebrae have specialized anatomy:
- Atlas (C1) — ring-shaped, no vertebral body or spinous process; articulates with the occipital condyles superiorly (atlanto-occipital joint) and with C2 inferiorly
- Axis (C2) — features the odontoid process (dens), which projects superiorly into the atlas ring; the dens is held against the anterior arch of C1 by the transverse ligament
See Atlas (C1) and Axis (C2) for detailed anatomy.
Facet Joint Orientation¶
Cervical facet joints are oriented approximately 45° to the axial plane, which allows significant flexion, extension, lateral bending, and rotation. This orientation also predisposes to facet dislocations during traumatic hyperflexion.
Clinical Pearl
The uncovertebral joints (joints of Luschka) are a common site of degenerative osteophyte formation, which can narrow the neural foramen and cause cervical radiculopathy. These are best seen on oblique radiographs or coronal CT reformats.
Imaging Findings¶
Radiography¶
- Lateral view — assess alignment (anterior and posterior vertebral body lines), lordosis, disc space heights, prevertebral soft tissues
- AP view — evaluate spinous process alignment, uncinate process hypertrophy, lateral masses
- Odontoid (open-mouth) view — assess C1–C2 alignment, lateral mass symmetry, dens integrity
| Measurement | Normal Value |
|---|---|
| Predental interval (adult) | ≤ 3 mm |
| Predental interval (child) | ≤ 5 mm |
| Prevertebral soft tissue (C2) | ≤ 7 mm |
| Prevertebral soft tissue (C6) | ≤ 22 mm |
CT¶
High-resolution CT with sagittal and coronal reformats is the study of choice for:
- Cervical fracture evaluation after trauma
- Uncovertebral and facet joint degenerative changes
- Foraminal stenosis assessment (oblique reformats)
- Pre-surgical planning
MRI¶
MRI is essential for evaluating the cervical spinal cord, discs, and ligaments:
| Structure | T1 Signal | T2 Signal |
|---|---|---|
| Normal spinal cord | Intermediate | Intermediate |
| Cord edema/myelopathy | Low | High |
| Normal disc | Intermediate | Bright (hydrated) |
| Desiccated disc | Intermediate | Dark |
| CSF | Dark | Bright |
Important
Increased T2 signal within the cervical spinal cord on MRI could suggest underlying myelopathy and is an important finding that may influence surgical decision-making. See Cervical Spondylotic Myelopathy.
Key Points¶
- The cervical spine (C1–C7) is the most mobile spinal segment
- Unique features include uncinate processes, transverse foramina, and bifid spinous processes
- C1 (atlas) and C2 (axis) have specialized anatomy distinct from the subaxial spine
- Facet joints are oriented at 45°, allowing multiplanar motion
- Prevertebral soft tissue swelling on lateral radiograph is an important indirect sign of injury
- MRI is critical for cord and soft tissue assessment
References¶
- Waxenbaum JA, Reddy V, Margetis K. Anatomy, Back, Cervical Vertebrae. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459200/
- Gaillard F, Bell DJ, et al. Uncovertebral joint. Reference article, Radiopaedia.org. Available from: https://radiopaedia.org/articles/uncovertebral-joint?lang=us
- Hartman J. Anatomy and clinical significance of the uncinate process and uncovertebral joint: a comprehensive review. Clin Anat. 2014;27(3):431–440. Available from: https://pubmed.ncbi.nlm.nih.gov/24453021/
- Raveendranath V, Kavitha T, Umamageswari A. Morphometry of the uncinate process, vertebral body, and lamina of the C3–7 vertebrae relevant to cervical spine surgery. Neurospine. 2019;16(4):748–755. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC6944996/
- Sangari SK, Dossous PM, Heineman T, Mtui EP. Dimensions and anatomical variants of the foramen transversarium of typical cervical vertebrae. Anat Res Int. 2015;2015:391823. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC4581543/
- Bruneau M, Cornelius JF, Marneffe V, Triffaux M, George B. Anatomical variations of the V2 segment of the vertebral artery. Neurosurgery. 2006;59(1 Suppl 1):ONS20–24. Available from: https://pubmed.ncbi.nlm.nih.gov/16888547/
- Bogduk N, Mercer S. Biomechanics of the cervical spine. I: Normal kinematics. Clin Biomech (Bristol). 2000;15(9):633–648. Available from: https://pubmed.ncbi.nlm.nih.gov/10946096/
- Yoganandan N, Pintar FA, Lew SM, Rao RD, Rangarajan N. Quantitative analyses of pediatric cervical spine ossification patterns using computed tomography. Ann Adv Automot Med. 2011;55:159–168. Available from: https://pubmed.ncbi.nlm.nih.gov/22105393/