Thoracic Spine

Question 1

What is the “Three column policy”?

Answer 1

Instability of the spine is present if 2 out of 3 columns are disrupted

• anterior column: anterior 2/3 of the vertebral body
• middle colum: posterior aspect of the vertebral body
• posterior column: posterior bone arch (spinous process)

are there any steps, kinks or breaks?

Question 2

Lateral Lumbar Spine
- (vertebral bodies size and shape?)

AP lumbar spine
- (pedicles?)

Answer 2

• contour is a smooth, unbroken arch
• vertebral bodies are the same heigh anteriorly and posteriorly
• the posterior margin of each vertebral body is slightly concave

On an AP image, pedicles become wider progressing from L1 to L5

Question 3

AP Thoracic Spine

- (lines?)

Answer 3

• left paraspinal line (interface between left lung and left posterior mediastinal soft tissue) should be touching the vertebral bodies
• no paraspinal line on lumbar spine

paraspinal line could be widened due to haematoma
two separate haematomas may make right paraspinal line bulge

Question 4

Assessing Lateral Images

Answer 4

• height or wedging of vertebral body= evidence of a compression #
• wedging may be associated with loss of normal concavitty of the posterior aspect of vertebral body and DISPLACEMENT OF MIDDLE COLUMN
• fragment of bone detached from anterior aspect?

Question 5

Assessing AP Images

• (paraspinal line?)
• (pedicles?)
• (transverse process?)

Answer 5

• widening or displacement of paraspinal line? - could mean haematoma
• abnormal widening of pedicles? could indicate # fragments have splayed apart
• # of transverse process?

Question 6

AP Thoracic Spine Positioning

Answer 6

• Detector is against patients back, arms by sides
• Centre 2.5cm below the sternal angle
• collimate tightly to the spine (4 fingers width), C7/T1 to T12/L1 junction
• 77kVP 15mAs (use AEC) - use a grid
• expose on arrested inspiration

Question 7

Lateral Thoracic Spine Positioning

Answer 7

• patient lies on their left side, arms raised in fornt of their face,
• centre on T7 - the inferior border of the scapula, 5cm anterior of the spinous process
• collimate to include C7/T1 to T12/L1
• 70kVp 40mAs (AEC)
• grid is used
• arrested inspiration

Question 8

AP Lumbar Spine Positioning

Answer 8

• patient lies on their back, arms by their side
• centre midline at the level of the lower costal margin (L3)
• arrested expiration
• collimate to include T12/L1 to L5/S1
• 77kVo 25mAs (AEC)
• grid is used

Question 9

Lateral Lumbar Spine Positioning

Answer 9

• patient lies on their left side, arms raised in front of their face, knees flexed
• centre over L3 - midway between lower costal margins and crests
• collimate to include T12/L1 to L5/S1
• 90kVp 35mAs (AEC)
• use a grid
• arrested expiration

Question 10

NAME THE PATHOLOGY

vertebral body slips out of position

Answer 10

spondylolisthesis

Question 11

NAME THE PATHOLOGY

stress fracture through the pars interarticularis

Answer 11

spondylolisis