Trauma X-ray - Axial skeleton
Thoracolumbar spine - Normal anatomy

Key points

  • Use a systematic approach
  • Correlate radiological findings with the clinical features
  • If 'instability' is suspected then further imaging with CT should be considered
  • If you see one fracture - check for another

Thoracolumbar spine - Systematic approach

  • Coverage - Adequate?
  • Alignment - Anterior/Posterior/Lateral
  • Bones - Cortical outline/Vertebral body height
  • Spacing - Discs/Spinous processes/Pedicles
  • Soft tissues - Paravertebral
  • Edge of image

In the context of trauma similar principles apply to imaging both the Thoracic spine (T-spine) and the Lumbar spine (L-spine). The plain X-ray anatomy and appearances of injuries to both these areas are discussed together.

Incorrect management of patients with spinal injury may cause or worsen neurological deficit. Therefore, patients with suspected spinal injury should be managed by experienced clinicians in accordance with local and national clinical guidelines. Imaging should not delay resuscitation.

Further imaging with CT or MRI (not discussed) is often appropriate in the context of a high risk injury, neurological deficit, limited clinical examination, or where there are unclear X-ray findings.

Good views of the T-spine and L-spine are difficult to achieve in the context of trauma. Clinical assessment is also often limited by distracting injuries or reduced consciousness. The clinico-radiological assessment of suspected T-spine or L-spine injuries therefore depends on careful consideration of both the clinical and radiological findings.

Thoracic spine - Standard views

AP and Lateral - Assess both views systematically (see box).

Images of the thoracic and lumbar spine are often large and the bones should be scrutinised in detail (see images below).

Note: The upper T-spine may not be visible on the lateral view - if injury is suspected here then a swimmer's view may be helpful - (see Cervical spine - Normal).

Thoracic spine systematic approach - Lateral and AP

Hover on/off image to show/hide findings

Tap on/off image to show/hide findings

Click image to align with top of page

Thoracic spine systematic approach - Lateral and AP

  • Coverage - The whole spine is visible on both views
  • Alignment - Follow the corners of the vertebral bodies from one level to the next
  • Bones - The vertebral bodies should gradually increase in size from top to bottom
  • Spacing - Disc spaces gradually increase from superior to inferior - Note: Due to magnification and spine curvature the vertebral bodies and discs at the edges of the image can appear larger than those in the centre of the image
  • Soft tissues - Check the paravertebral line (see AP image below)
  • Edge of image - Check the other structures visible

T-spine normal anatomy - Lateral (detail)

Hover on/off image to show/hide findings

Tap on/off image to show/hide findings

Click image to align with top of page

T-spine normal anatomy - Lateral (detail)

  • Alignment - Vertebral body alignment is assessed by carefully matching the anterior and posterior corners of the vertebral bodies with the adjacent vertebra
  • Bones - Gradual increase in vertebral body height from superior to inferior
  • Spacing - Disc spaces gradually increase in height from superior to inferior
  • VB = Vertebral body
  • P = Pedicle
  • SP = Spinous process (ribs overlying)
  • F = Foramen - spinal nerve root exit

T-spine normal anatomy - AP (detail)

Hover on/off image to show/hide findings

Tap on/off image to show/hide findings

Click image to align with top of page

T-spine normal anatomy - AP (detail)

  • Alignment - The vertebral bodies and spinous processes (SP) are aligned
  • Bones - The vertebral bodies and pedicles are intact
  • Other visible bony structures include the transverse processes (TP), ribs, and the costovertebral and costotransverse joints
  • Spacing - Each disc space is of equal height when comparing left with right. The pedicles gradually become wider apart from superior to inferior
  • Soft tissue - Note the normal paravertebral soft tissue which forms a straight line on the left - distinct from the aorta

Lumbar spine - Standard views

AP and Lateral

The whole L-spine should be viewed in both views.

Divergence of the X-ray beam may limit assessment of the low lumbar spine levels - a further 'coned lumbosacral view' centred at the level of the lumbosacral junction may be helpful.

L-spine systematic approach - Lateral

Hover on/off image to show/hide findings

Tap on/off image to show/hide findings

Click image to align with top of page

L-spine systematic approach - Lateral

  • Coverage - The whole L-spine should be visible on both views
  • Alignment - Follow the corners of the vertebral bodies from one level to the next (dotted lines)
  • Bones - Follow the cortical outline of each bone
  • Spacing - Disc spaces gradually increase in height from superior to inferior - Note: The L5/S1 space is normally slightly narrower than L4/L5

L-spine normal anatomy - Lateral (detail)

Hover on/off image to show/hide findings

Tap on/off image to show/hide findings

Click image to align with top of page

L-spine normal anatomy - Lateral (detail)

  • Check the cortical outline of each vertebra
  • The facet joints comprise the inferior and superior articular processes of each adjacent level
  • The pars interarticularis literally means 'part between the joints'
  • P = Pedicle
  • SP = Spinous process

L-spine systematic approach - Normal AP

Hover on/off image to show/hide findings

Tap on/off image to show/hide findings

Click image to align with top of page

L-spine systematic approach - Normal AP

  • Alignment - The vertebral bodies and spinous processes are aligned
  • Bones - The vertebral bodies and pedicles are intact
  • Spacing - Gradually increasing disc height from superior to inferior. The pedicles gradually become wider apart from superior to inferior - Note: The lower discs are angled away from the viewer and so are less easily assessed on this view

L-spine normal anatomy - AP (detail)

Hover on/off image to show/hide findings

Tap on/off image to show/hide findings

Click image to align with top of page

L-spine normal anatomy - AP (detail)

  • Check carefully for pedicle integrity and transverse process fractures

Three column model

The clinico-radiological assessment of thoracolumbar spine stability is usually performed by spinal surgeons with the help of radiologists.

A simple model commonly used for assessment of spinal stability is the 'three column' model. This states that if any 2 columns are injured then the injury is 'unstable'. This theory is an over simplification if applied to plain X-rays alone. It is important to be aware that some injuries are not visible on X-ray and that 2 and 3 column injuries may be underestimated as 1 or 2 column injuries respectively.

If spinal instability is suspected on the basis of clinical or radiological grounds then further imaging with CT should be considered.

Three column model - Anatomy

Hover on/off image to show/hide findings

Tap on/off image to show/hide findings

Click image to align with top of page

Three column model - Anatomy

  • Anterior column = Anterior half of the vertebral bodies and soft tissues
  • Middle column = Posterior half of the vertebral bodies and soft tissues
  • Posterior column = Posterior elements and soft soft tissues

Three column model - Fracture simulation

Hover on/off image to show/hide findings

Tap on/off image to show/hide findings

Click image to align with top of page

Three column model - Fracture simulation

  • Injuries 1 and 2 affect one column only and are considered 'stable'
  • 1 - Spinous process injury
  • 2 - Anterior compression injury
  • Injuries 3 and 4 affect two or more columns and are considered 'unstable'
  • 3 - 'Burst' fracture
  • 4 - Flexion-distraction fracture - 'Chance' type injury