Queckenstedt's maneuver is a clinical test, formerly used for diagnosing spinal stenosis.
Given normal anatomy, the intracranial pressure will be reflected as a rapidly rising pressure measured from the lumbar needle, within 10–12 seconds.
If there is a stenosis in the spine, there will be a damped, delayed response in the lumbar pressure, thus a positive Queckenstedt's maneuver.
Nowadays this test has been made mostly superfluous by superior imaging modalities like MRI and CAT.
[1] The test is named after Hans Heinrich Georg Queckenstedt who described it in 1916.