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).

Thoracic

• 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.

Lumbar

• 5 vertebrae of the lower back.
• Large bodies.
• Spinous processes are typically short, and more horizontally oriented.
• Short transverse processes.

Sacral/Coccygeal

• 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.

Vertebral (aka, neural) arch

• Pedicles
• Laminae
• Transverse processes
• Spinous process
• Superior and inferior articular processes for articulation with vertebrae above and below

Vertebral foramen

• Space between body and arch
• When stacked, vertebral foramina create vertebral canal, through which spinal cord passes

Intervertebral foramen

• Where spinal nerves pass through vertebral column laterally

Intervertebral disc

• 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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