Fig. 1
From: Severity and location of lumbar spine stenosis affects the outcome of total knee arthroplasty
Anterior–posterior (AP) diameter. A Sagittal T2-weighted MRI image at the intervertebral disc space between lumber level 1 and 2. B The corresponding T2-weighted axial MRI image from which the AP diameter measurement is shown. A line drawn from anterior-most aspect of the thecal sac to the most posterior aspect yields the measurement needed to assess stenosis in the AP plane