The remaining five cervical vertebrae, C3-C7, form the lower cervical spine. It also has heavy pedicles, laminae and transverse processes that help in the attachment of muscles. The axis possesses a large vertebral body with the odontoid process or dens. The superior articular facets articulate with the occipital condyles and are kidney-shaped, concave, projecting upward and inward, while the inferior articular facets are comparatively flat, projecting downward and inward, and articulate with the superior facets of the axis. A zygapophyseal joint is present on the superior and inferior aspect of the lateral mass. The transverse process surrounds the transverse foramen, through which the vertebral artery passes. The atlas comprises of a thick anterior arch, a thin posterior arch, two prominent lateral masses, and two transverse processes. The transverse ligament firmly opposes the odontoid process to the posterior portion of the anterior arch of atlas and provides stability to the atlantoaxial joint. The odontoid process or dens of the axis represents the fused remnants of the body of the atlas. In contrast to other vertebrae, the atlas is ring-shaped without a body.
Generally, the atlantoaxial joint is accountable for half of the cervical rotational movements while the atlanto-occipital joint is responsible for half of the flexion and extension movements of the neck. The atlas vertebra articulates with the occiput superiorly at the atlanto-occipital joint and with the axis inferiorly at the atlantoaxial joint. The upper cervical spine comprises of the atlas (C1) and axis (C2), which are different from rest of the cervical vertebrae. In contrast to other parts of the spine, the cervical spine has transverse foramina in each vertebra through which the vertebral arteries supply blood to the brain.īased on the structural diversity in the cervical spine, it can be divided into two parts: the upper and lower cervical spine. The cervical spine is highly mobile compared to the thoracic or lumbar spine. The cervical spine comprises of the first 7 vertebrae, which form the neck. The spine can be divided into 4 parts: cervical, thoracic, lumbar and sacral region. The purpose of the canal is to create a bony casing from the head to the lower back, through which the spinal cord passes. The spinal canal is formed by the placement of single vertebral foramina one on top of the other to form a canal. The spinous process forms a steeple at the apex of the laminae and is the part of our spine that is felt directly under the skin. The transverse processes spread out from the side of the pedicles like wings and help to anchor the surrounding muscle to the vertebral arch. The laminae of the vertebra can be described as a pair of flat-arched bones that form a component of the vertebral arch. Two strong pedicle bones join the vertebral arch to the body of the vertebrae. The body is cylindrical in shape, strong and stable. Parts of a VertebraĪ single vertebra is made up of two parts, the front portion is called the body and the back portion is referred to as the vertebral or neural arch. The vertebrae and discs form the spinal column from the neck to the pelvis, giving symmetry and support to the body.
It is made up of bony segments called vertebrae with fibrous tissue called intervertebral discs between them. The spine, also called the backbone, plays a vital role in stability, smooth movement and protection of the delicate spinal cord.
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