| DCRA |
Definition |
| Mean vertebral
depth |
Mean of distances
of corners 1 and 2 and corners 3 and 4 |
| Sagittal plane
angel |
Angle between
vertebral midplanes, which is defined as the line running through
midpoints between corners 1 and 3 and 2 and 4, respectively. |
| Disc height |
Sum of the
distances from the corners 2 and 4 from the bisectrix between midplanes,
divided by the mean depth of the cranial vertebra. As disc height
depends linearly on sagittal plane angle, a correction is applied in
order to permit comparisons among radiographs taken in different
postures of the lumbar spine. |
| Sagittal
translation or postero-anterior
(dorso-ventral)
displacement |
Distance between
the projections of the centre points (geometric center of corners 1-4)
of the vertebrae onto the bisectrix, divided by the mean depth of the
cranial vertebra. Displacement is counted positive if the cranial
vertebra is displaced in anterior direction with respect to the caudal
vertebra. Similar to disc height a correction is applied in order to
permit comparisons among radiographs taken in different postures of the
lumbar spine. |
Printed with permission from G. Leivseth