Radiological measurements of the SPINE.

1. Radiographic Measurements
Noorulain Iqbal

2. The identification,
classification and
appropriate treatment of
spinal deformities depend
to a large degree upon their
proper radiographic
evaluation.

3. 1st Step
• The Nature
• The Location

4. Location
• Basis of the location of the
apex of the curve
• The apex is the vertebra or
disc that is maximally laterally
displaced and minimally
angulated

5. • Thoracic : T2 – T11 T12 Disc
• Thoracolumbar: T12 – L1
vertebrae
• Lumbar: at or distal to L1 –
L2 disc

6. Cobb Technique
• The angular magnitude of a
spinal deformity
• The proximal endplate of
the proximal end vertebra
and the distal endplate of
the distal end vertebra are
used.

7. Apical Vertebral Translation (AVT)
• Lateral displacement
of the apex of a
coronal curve relative
to the center sacral
vertical line ( CSVL ).

9. Sagittal Balance
• C7 Plumb line on lateral
xray
• The distal reference
point is posterosuperior
corner of the sacrum

12. C2-C7 SVA
• The Distance between
– the plumb line of C2 dens tip
– plumb line of the center of the C7 upper end plate

14. C2-C7 Angle
• Angle between
– Horizontal line of C2
lower end plate
– Horizontal line of C7
lower end plate

15. T1 SLOPE
• The angle between a
horizontal line ( of the
radiograph) and the
upper end plate of T1

16. C2-T1 Pelvic Angle (CTPA)
Angle formed by
– a line extending
from the center of
the C2 vertebral
body to the
bicoxofemoral
axis
– a line from the
bicoxofemoral
axis to the center
of the T1
vertebral body.

17. T1 Pelvic Angle (TPA)
Angle formed by
• a line extending from
the center of T1 to the
bicoxofemoral axis
• a line from the
bicoxofemoral axis to
the center S1 endplate
• Mean: 11.9
• >20 = Deformity

18. Pelvic Parameters
• Pelvic Tilt
– Angle between the
vertical and the line
through the midpoint of
the sacral point to
femoral head axis
– Mean pelvic tilt in volunteer
population of 13 degrees ( Lafage
Spine, 2009)

19. • Sacral slope
– Angle between the
horizontal line and the
sacral plate
• Pelvic Incidence
– Angle between line
perpendicular to the
sacral plate at its
midpoint
– The line connecting this
point to the femoral
head axis