Lumbar spine and pelvis

• Spinal Subsystems

  • SPINAL MUSCLES - An active subsystem that provides dynamic stability
  • SPINAL COLUMN - A passive subsystem that provides intrinsic stability
  • THE NEURAL CONTROL UNIT - Evaluating stability and coordinating a response
• Lumbar Region Function

  • Surrounds and protects the spinal cord from injury
  • Accepts and distributes load
  • Produces and accumulates moments of force
  • Serves as an attachment point for muscles
• Spinal Regions

  • CERVICAL REGION > 7 VERTEBRAE > LORDOSIS
  • THORACIC REGION > 12 VERTEBRAE > KYPHOSIS
  • LUMBAR REGION > 5 VERTEBRAE > LORDOSIS
  • SACRUM
• Lumbar versus Thoracic Differences

  • Shape and size of neural canal
  • Shape and size of vertebral body
  • Presence/absence of rib 'demifacets'
  • Shape, length and angle of spinous process
  • Orientation of facet joint surfaces
• Facet (Apophyseal/Zygapophyseal) Joints

  • Sagittal (Side)View
  • Inferior Articular Process
  • Superior Articular Process
  • Facet joint structure allows gliding and/or distraction
  • Facet joint approximation can limit movement
• Facet Joint Angle

  • Cervical facets allow all movements
  • Thoracic facets favour lateral flexion and rotation, some forward flexion/extension
  • Lumbar facets allow lateral flexion and forward flexion/extension, minimal rotation
• Spinal Ligaments

  • FORWARD FLEXION
  • EXTENSION
• Spinal Nerves

  • 31 pairs
  • 5 in lumbar region
  • 5 in sacral region
  • 1 in coccygeal region
  • The lumbar (and cervical) regions are enlarged, to accommodate nerve plexi
• Spinal Cord

  Nerve roots exit via intervertebral foramina
• Cauda Equina


  • The spinal cord is shorter than the spinal column, ending level with the L1/L2 vertebrae
  • Nerves roots below L1/L2 are elongated to accommodate this
  • Compression of the cauda equina can be a medical emergency
• Myotomes

  • L2 = Hip flexion
  • L3 = Knee extension
  • L4 = Foot dorsiflexion
  • L5 = Big Toe Extension
  • S1 = Eversion of the foot
  • S2 = Knee flexion
  • S3–S4 = Pelvic floor, bladder and genital function
• Dermatomes

  • L3/4 = Knee Jerk
  • S1/2 = Ankle Jerk
• Pelvis Structure

  • Inominate Bone
  • Ilium
  • Ischium
  • Pubis
  • Sacrum
  • Sacral foramina
  • Sacroiliac Joints [SIJ]
  • Interaction between inominates and sacrum
• Pelvis Function

  • Supports and protects the viscera
  • Supports bodyweight transmitted through vertebrae
  • Is a significant attachment point for lumbar musculature and ligaments
• Physiological Movements

  • Extension
  • Forward Flexion
  • Lateral Flexion
• Additional Lumbar Musculature

  • Transverse Abdominis
  • Latissimus Dorsi
• Function of lumbar spine

  • STABILITY
  • CONTROL
  • MOTION