What is the modified Schober test?
The modified Schober test measures mobility of the thoracolumbar spine during maximum active lumbar flexion. Two midline marks are drawn originating from the dimples of Venus (approximately at the S2 level; just inferior to the posterior, superior iliac spines) and 10 cm superior to that location in an upright patient. The distance between the marks is again measured with the patient’s back at maximal flexion with the knees locked in maximal extension. A difference of <5 cm between neutral and flexion is suggestive of an inflammatory spondyloarthropathy. Limitation of lateral bending, reduced chest wall expansion during maximum inspiration, and restricted rotation of the thoracic spine with the pelvis held stable in a standing patient also support this diagnosis
