The Spine

Anatomy & Physiology

  • 7 cervical vertebra
  • 12 thoracic vertebra
  • 5 lumbar vertebra
  • 5 sacral vertebra – fused
  • 4 coccygeal vertebra – fused


  • C1-7 nerve roots exit above cervical vertebra
  • C8-onwards exit below vertebra
  • Spinal cord finishes at L1 in adults
  • Cauda equina finishes at S2








Haemopoietic function

  • Marrow of vertebral bodies retains blood-forming capacity throughout life
    • Vertebrae subject to blood-borne diseases and diseases of haemopoietic system
      • Infection
      • Primary haematological malignancies
        • Myeloma
        • Metastatic disease

Spinal cord and nerve root transmission

  • Spinal cord contains UMNs
    • Highly susceptible to damage
      • Rapid compression, movement, ischaemia
  • Do not recover well, even if decompressed
  • Slower forms of spinal cord compression respond better than acute
    • E.g. metastatic tumour deposits, infection
    • Cauda equine
      • LMNs
      • Less easily damaged by movement/compression
        • Decompression may produce recovery
        • Exception – cauda
          equina syndrome:
  • Sacral nerve roots supplying bladder, bowel + sexual function
  • Rapid decompression needed to improve probability of recovery


Red Flags

  1. New pain <10 or >60 yrs
  2. Hx Ca
  3. Hx osteoporosis or prolonged steroids + minor trauma
  4. Hx HIV or immunosuppressed
  5. Non-mechanical low back pain with night pain or thoracic pain
  6. Rapid onset neurological symptoms
  7. Bladder and bowel dysfunction


Presentation often with axial pain (related to axial skeleton – i.e. neck or lower back) and radicular pain (upper/lower limb in dermatomal/myotomal distribution). Radicular pain easier to treat than axial pain.




Traumatic Conditions


  • Based on Denis’ 3 column theory
  • Fracture to one column usually stable, whilst 2 or more results in an unstable fracture

  • Stabilisation of the spine most commonly achieved with pedicle screws:
    • Access posteriorly and resect away supraspinous and interspinous ligs
    • Identify pars interarticularis or lamina just medial to transverse process
    • ?remove part of medial facet joint – better surface for screw
    • Advance screw through lamina into pedicle in affected vertebra and adjacent vertebra
      • Avg size screw 7x45mm
  • Secure screws with vertical rod
  • Apply bone graft laterally
  • Image below:
    • Bottom – basic stabilisation
    • Whole image – circumferential stabilisation













L4/5 Stabilisation + intervertebral disc implant (RD+E use allogenic bone graft (donated femoral head) mixed with patient marrow)









  • Neurological deficit implies unstable injury
    • Requires stabilisation
    • Deteriorating neurological function is absolute indication for stabilisation
      • Often also requires decompression
      • Deficit may be spinal cord injury (UMN) or cauda equina/nerve root (LMN)


Spinal Cord Injury

  • Fracture is most common – injury to cord occurring at time of fracture
  • Injury may be complete or incomplete
    • First 24-48 hrs cord goes into ‘spinal shock’
    • An apparently complete injury may be incomplete
    • Complete motor loss with a positive bulbo-spongiosus reflex = bad prognostic indicator
    • Initial management:
  1. Avoid further injury – in-line immobilisation, log rolling, rigid cervical collars
  2. Maintain BP (systolic 90-100 mmHg) + oxygenation
  3. Urinary catheter (patient will be in retention)
  4. NG tube (for paralytic ileus)
  5. Pressure area care
  • Complete spinal cord injuries make no recovery
  • Level of injury determines function:
    • Thoracic = paraplegia
      • Loss of function and sensation in lower limbs, including bladder and bowel control
  • Cervical = quadriplegia
    • Paralysis with varying degree of upper limb involvement depending on level
  • Above C4 seldom survive
    • Diaphragmatic function lost and no voluntary respiratory function
    • Incomplete injuries make some recovery
      • Usually progress to walking


Bulbo-spongiosus reflex (bulbocavernous reflex (BCR), Osinski reflex) – primitive polysynaptic reflex useful in testing for spinal cord injury - normally suppressed by higher cortical function. Test involves monitoring anal sphincter contraction in response to applying pressure to the glans penis or tugging on an indwelling Foley catheter. Tests sensory and motor S2-4 nerve roots. Absence of reflex without sacral spinal trauma (S2-4) indicates spinal shock. Lack of motor or sensory function after the reflex has returned indicates complete spinal cord injury (i.e. cord is no longer ‘shocked’ and should therefore be functional but there is discontinuity between the brain and the sacral roots so the reflex is no longer suppressed). Poor prognostic indicator. 

Cervical Spine

  • Suspect in unconscious patients with significant trauma and patients reporting even mild neurological symptoms following an accident
  • Investigations:
    • Lateral C spine x-ray
      • C7/T1 must be visible for this to be adequate
      • Inspect                 for:
        • Adequacy
        • Bony alignment
        • Vertebral body fractures
        • Facet joint fractures/dislocations
        • Spinous process fractures
        • Increased soft tissue shadow suggestive of injury
        • And AP and open mouth view should then be obtained
          • Indications for CT:
            • Fracture visible or suspected on XR
            • Neurological deficit
            • Head injury requiring CT










  • MRI if:
    • Any neurological deficit
      • Cervical facet dislocations before reduction
        • Significant disc protrusion into spinal canal may cause neurological deficit on attempted reduction of the dislocation
        • Treatment:
          • More stable – rigid collar (Aspen or Philadelphia)
          • Less stable – halo-vest -->
          • Unstable – anterior and/or posterior instrumented stabilisation and fusion


Fractures of the Atlas (C1, Jefferson fracture)

  • Fractured in 4 places as result of vertical compression force
    • Stable
    • Cord damage uncommon
    • Difficult to detect on plain x-ray
    • CT confirmation necessary
    • Treatment:
      • Collar


Fractures of the Odontoid Peg (C2)

  • Common and easily missed
  • Fracture at base of peg
  • Considerable displacement possible
  • Lateral radiograph shows fracture
  • Young patients – halo-vest for 8-12/52 or stabilisation with anterior screws across fracture
  • Non-union in 30-70%
    • C1/2 posterior fusion 

Hangman’s Fracture (C2/3 traumatic spondylolisthesis)

  • Pedicle fractures of C2 allow forward subluxation of C2 on C3
  • Degrees of severity – traction rarely needed
  • Treatment:
    • Less severe – rigid collar/halo-vest
    • More severe – anterior C2/3 discectomy and fusion

Spondylolisthesis – forward dislocation of a vertebra over the one beneath it.










Subaxial Injuries (C3-C7)

  • Vertebral body fractures
    • Stable – collar immobilisation
    • Shattered with posterior complex injury – corpectomy and reconstruction with iliac crest bone graft
    • Facet joint dislocation
      • Unilateral or bilateral
      • ?fracture of facet joint
      • Detected on lateral radiograph – subluxation of superior vertebral body on inferior
        • 25% subluxation suggests unifacet
        • 50% à bifacet dislocation
  • Early reduction advised – after MRI to exclude protrusion into canal

Whiplash Injuries

  • Soft-tissue injuries – neck/low back
    • Usually when car hit from behind
    • Symptoms:
      • Pain in neck
      • ?radiation down the arm
      • ?paraesthesiae or numbness in the arm or hand
      • Onset of symptoms delayed by few hours
        • Sometimes days
        • Treatment:
          • Symptomatic with analgesia
          • Early mobilisation
          • Most recover, some continue to have symptoms over a lon