Vertebral Column
Vertebral column (aka, spinal column, aka, spine)
- It encloses and protects the spinal cord.
- It provides attachment sites for muscles of the head, neck, and trunk.
- The individual vertebrae are named according to their region and vertical order. For example, T1 is the first vertebra of the thoracic region.
- The S- shaped curve of the vertebral column facilitate its flexibility and resilience.
Regions of the Vertebral Column:
Cervical
- 7 vertebrae within the neck.
- C1 and C2 have unique anatomical features to support the skull.
- Small bodies.
- Transverse foramen for vertebral arteries.
- Spinous processes of cervical vertebrae 2-6 are bifid (aka, bifurcated).
- 12 vertebrae that articulate with ribs to form posterior wall of thoracic cage.
- Bodies have costal facets for articulations with the ribs.
- Spinous processes are typically longer and angled inferiorly.
- Transverse processes have costal facets for articulation with ribs.
- 5 vertebrae of the lower back.
- Large bodies.
- Spinous processes are typically short, and more horizontally oriented.
- Short transverse processes.
- 5 fused sacral bones.
- 3-4 fused coccygeal bones.
- Contribute to posterior wall of the pelvis.
General Features of Vertebrae:
Vertebral body (aka, centrum)
- The disc-shaped weight-bearing portion of the vertebra.
- Pedicles
- Laminae
- Transverse processes
- Spinous process
- Superior and inferior articular processes for articulation with vertebrae above and below
- Space between body and arch
- When stacked, vertebral foramina create vertebral canal, through which spinal cord passes
- Where spinal nerves pass through vertebral column laterally
- Absorbs shock and acts as a cushion between the vertebrae, and allows for spinal flexibility.
- It comprises:
- The nucleus pulposus, which is an inner gelatinous substance
- The anulus fibrosus is the outer ring of collagen and cartilage that encloses the nucleus pulposus
Clinical correlations:
- Distorted spinal curvatures can be caused by poor posture, aging, disease, and other factors.
- Scoliosis, which is a common curvature abnormality, is characterized by a lateral curvature of the vertebral column.
- Herniated intervertebral discs are common; they occur when a fissure in the annulus fibrosus allows the nucleus pulposus to bulge and compress nearby nerves, which can cause deficits and pain.
See: Spinal cord compression.
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