Vertebral Column Anatomy

Vertebral Column Objectives

• Understand the organization of vertebrae and normal vertebral column curvatures
• Identify features of the cervical, thoracic, and lumbar vertebrae
• Identify parts of the sacrum
• Distinguish between cervical, thoracic, and lumbar vertebrae
• Explain how ligaments attach to the vertebral column

Regions of the Vertebral Column

• Cervical region has 7 vertebrae
• Thoracic region has 12 vertebrae
• Lumbar region has 5 vertebrae
• Sacral region has 5 fused vertebrae
• Coccygeal region has 3-4 fused vertebrae

Curves of the Vertebral Column

• The vertebral column of newborns is concave forward
• The newborn's curvature changes in two regions
• The adult vertebral column has 4 curvatures

Cervical Curve

• The cervical curve is convex forward
• It is a secondary curve that appears in the 3rd month, when the child raises their head

Thoracic Curve

• The thoracic curve is concave forward
• It is a primary curve present from birth

Lumbar Curve

• The lumbar curve is convex forward
• It is a secondary curve appearing during the 9th-18th month when the child learns to sit and walk

Pelvic (Sacral)Curve

• The pelvic (sacral) curve is concave forward
• It is a primary curve present from birth

Abnormal Curvatures: Kyphosis

• Kyphosis is an exaggerated kyphotic (posterior) curvature in the thoracic region
• Kyphosis is commonly observed in osteoporosis

Abnormal Curvatures: Lordosis

• Lordosis is an exaggerated lordotic (anterior) curvature in the lumbar region
• Temporary lordosis is common in pregnant women

Abnormal Curvatures: Scoliosis

• Scoliosis is a lateral curvature of the vertebral column
• Scoliosis may result from unequal growth of the two sides of one or more vertebrae

Structure of the Vertebrae

• The vertebral body carries weight
• The vertebral arch is also called the neural arch
• The structure of the vertebrae is as follows:
  • Body
  • Vertebral (neural) arch
  • Pedicle
  • Lamina
  • Spine
  • Transverse process
  • Vertebral foramen
  • Superior articulating process
  • Inferior articulating process
  • Intervertebral foramen, which has nerves pass through

Intervertebral Disc

• The intervertebral discs position themselves between the vertebral bodies and are fused with them
• The intervertebral discs consists of 2 parts:
  • An outer circular fibrous ring: annulus fibrosus, formed of crisscrossed, tight collagen fibers that connect the adjacent vertebrae
  • A central gelatinous spongy center: nucleus pulposus in the middle; it consists of 80% water
• Intervertebral discs act as shock absorbers
• Intervertebral discs goes through an aging process
  • Decreases in water content
  • Becomes thinner
  • Loses elasticity
  • Causes bone-on-bone friction

Intervertebral Disc Prolapse

• Intervertebral disc prolapse, also called disc dislocation, has what inside that will resemble an oreo biscuit
• Herniation or protrusion of the nucleus pulposus into the anulus fibrosus causes lower back pain (LBP) and lower limb pain
• Nucleus pulposus herniations usually extend posterolaterally where the anulus fibrosus is relatively thin with little support from the longitudinal ligaments
• A posterolateral herniated IV disc is more likely to cause symptoms because it compresses the spinal nerve roots

Cervical Vertebrae

• Cervical Vertebrae can be identified by the presence of a foramen in the transverse process
• C1 is known as the "atlas", has no body, no spine, and has an anterior and posterior arch
• C2 is known as the "axis" and has dens
• From C3 to C6, is typical cervical vertebrae has a bifid spine
• C7 the last cervical vertebrae spine is not bifid
• The Atlanto-occipital Joint articulation lies between the two superior facets of the atlas and the occipital condyles of the skull; its type is synovial condyloid (ellipsoid)
• The Median Atlanto-axial joint is synovial pivot
  • Ring: ring anterior arch of the atlas & the transverse ligament
  • Pivot: dens of the axiss

Ligaments of the Atlanto-Axial Joint

• Alar Ligament
• Cruciate Ligament

Thoracic Vertebrae

• Thoracic vertebrae are identified by the presence of costal facets for articulation with the heads of ribs
• The body is intermediate in size between the cervical and lumbar vertebrae.

Lumbar Vertebrae

• Lumbar vertebrae have a large body
• They do not have costal facets or transverse process foramina

Sacral and Coccygeal Vertebrae

• The Sacral region has 5 fused vertebrae (S1-S5) forming the sacrum
• The Coccygeal region has 4 fused vertebrae forming the coccyx, and is called the tailbone

Ligaments of the Vertebral Column

• Ligaments of the vertebral column are relative to the body of the vertebra
  • Anterior longitudinal
  • Posterior longitudinal
  • Supraspinous
  • Interspinous
  • Ligamentum flavum