Anatomy of the Spine

Summary

  • Functions of the spine
  • Anatomy of the spine
  • Spinal vulnerability to trauma

Functions of the Spine

  1. Protection (particularly of the spinal cord)
  2. Mobility
    • There is significant mobility at individual facet joints between vertebrae
    • The cumulative effect of this adds up
    • Mobility differs by region
      • Movement  is greatest in cervical/lumbar movements
  3. Haematopoesis
    • The is significant cancellous bone within the vertebral bodies
    • Venous plexus in vertebral body
  4. Communication
    • IV foramen allow neurovascular passage

 


Anatomy of the Spine

  • There are several anatomical features with their own functions
  • IV discs – 25% of the length of the spine is made up by these
    • These are strong and can withstand pressure
    • ↓Size with age as ↓hydration => decreased height
  • Spinous processes
    • These restrict movement (specifically hyperlordosis)
    • ↑SA for ligament attachment
Spinal Curvatures
  • Primary curvature – thoracic + sacral (these are present before birth)
  • Secondary curvatures – Lumbar + cervical
  • Lumbar lordosis
    • Inward curving
    • Exaggerates during pregnancy to maintain balance through hip
  • Thoracic kyphosis
    • Outward curving
    • Can be pathological – Hunchback
  • Scoliosis
    • Lateral curvature
    • Often pathological
Image outlining the normal curvatures of the spine.

Spinal vulnerability

  • Some aspects of the spine have compromised stability for mobility
    • Particularly C- and L-spine
    • L-spine is prone to injury from ↑load
    • C-spine is prone to injury from hyperflexion/hyperextension
  • The spine is particularly vulnerable at static-dynamic junctions
    • e.g. Sacrum-lumbar junction and spinal-skull junction
  • Spine is prone to:
    1. Fractures
    2. IVD herniation
      • Weak posterolaterally
  • Cauda equina syndrome (CES)
    • Loss of cauda equina function
    • Often iatrogenic – lumbar puncture
    • Causes incontinence