Specific Features of the Cervical Spine
The cervical spine consists of 7 vertebral segments and 8 cervical nerve roots. The C1 and C2 segments have distinctive shapes whereas C3-C7 share a similar appearance. C1 does not have a vertebral body, and is instead made up of anterior and posterior arches that are connected by lateral masses on either side. C2 supports C1 and allows for rotation at the C1-C2 joint. One of the unique features of C2 is the dens or odontoid process which is a superiorly projecting component that articulates with the anterior arch of C1.
Unique features of the cervical spine include the foramen transversarium and the uncinate process. The foramen transversarium are holes within the transverse processes of the C spine that transmit the vertebral artery. It is important to understand this relationship especially in trauma patients with cervical spine injury. If a patient has a fracture of the C spine that extends into the foramen trasnversarium, this patient may have a vertebral artery injury and a vascular study such as a CTA or MRA should be performed.
Axial and Sagittal diagrams of a typical C3-C7 vertebral segment.
Coronal diagram of C1-C2. Notice the dens arising from the body of C2 which articulates with the anterior arch of C1.
Sagittal diagram of C1-C2 with ligaments